Math Is Fun Forum

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

.

#7551. The average of five numbers is 306.4. The average of the first first two numbers is 431 and the average of the last two numbers is 214.5. What is the third number?

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Monox D. I-Fly

Member

From: Indonesia

Registered: 2015-12-02

Posts: 2,000

Re: 10 second questions

---

Actually I never watch Star Wars and not interested in it anyway, but I choose a Yoda card as my avatar in honor of our great friend bobbym who has passed away.
May his adventurous soul rest in peace at heaven.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

The solution #7551 is correct. Neat work!

#7552. The average age of a man and his son is 48 years. The ratio of their ages is 11 : 5 respectively. What will be the ratio of their ages after 6 years?

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Monox D. I-Fly

Member

From: Indonesia

Registered: 2015-12-02

Posts: 2,000

Re: 10 second questions

---

Actually I never watch Star Wars and not interested in it anyway, but I choose a Yoda card as my avatar in honor of our great friend bobbym who has passed away.
May his adventurous soul rest in peace at heaven.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

The solution #7552 is correct. Neat work!

#7553. The average age of 80 girls was 20 years, the average age of 20 of them was 22 years and that of another 20 was 24 years. Find the average age of the remaining girls.

---

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Monox D. I-Fly

Member

From: Indonesia

Registered: 2015-12-02

Posts: 2,000

Re: 10 second questions

---

Actually I never watch Star Wars and not interested in it anyway, but I choose a Yoda card as my avatar in honor of our great friend bobbym who has passed away.
May his adventurous soul rest in peace at heaven.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

Good attempt!

#7554. In a family, the average age of father and mother is 38 years whereas the average age of father, mother, and their only daughter is 28 years. Find the age of the daughter.

---

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Monox D. I-Fly

Member

From: Indonesia

Registered: 2015-12-02

Posts: 2,000

Re: 10 second questions

---

Actually I never watch Star Wars and not interested in it anyway, but I choose a Yoda card as my avatar in honor of our great friend bobbym who has passed away.
May his adventurous soul rest in peace at heaven.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

The solution #7554 is correct! Neat work!

#7555. The average age of 30 boys in a class is 15 years. One boy aged 20 years left the class, but two new boys came in his place whose ages differ by 5 years. If the average age of all the boys now in the class still remains 15 years, find the age of the younger newcomer.

---

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

#7556. In a class, there are 40 boys and their average age is 16 years. One boy, aged 17 years, leaving the class and another joining, the average age becomes 15.875 years. Find the age of the new boy.

---

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

#7557. The average number of toffees with 6 friends is 10. If each of them eats one toffee, then find the average number of toffees with them, now.

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

#7558. The salary of five members of a family is $10,000, $12,000, $17,000, $15,000, and $14,000. Find the average salary of all the members of the family using assumed mean.

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

#7559. Out of seven given numbers, the average of the first four numbers is 4 and that of the last four numbers is also 4. If the average of all the seven numbers is 3, find the fourth number.

---

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

#7660. The average age of a man and his son is 35 years. The ratio of their ages is 5 : 2 respectively. What is the son's age?

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

#7661. The average salary of A, B, and C is $35000 per annum. Also, the average salary of D and E is $38000 per annum. What is the average salary per annum of all the five taken together?

---

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Monox D. I-Fly

Member

From: Indonesia

Registered: 2015-12-02

Posts: 2,000

Re: 10 second questions

---

Actually I never watch Star Wars and not interested in it anyway, but I choose a Yoda card as my avatar in honor of our great friend bobbym who has passed away.
May his adventurous soul rest in peace at heaven.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

.

Neat work!

#7662. The average age of 8 persons is increased by 2 years when one of them, whose age is 24 years is replaced by a new person. Find the age of the new person.

---

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

#7663. The average of coins with a group of friends reduces by 1, when one friend having 20 coins leaves the group. Find the number of friends left in the group given that originally, average of coins was 15.

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

#7664. Find the average of squares of natural numbers up to 6.

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

#7665. Find the average of cubes of natural numbers up to 12.

---

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

#7666. The average weight of 3 group of friends of 50, 30, and 20 members respectively are 50 kilograms, 52 kilograms, and 55 kilograms. What is the average weight of all the friends taken together?

---

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Monox D. I-Fly

Member

From: Indonesia

Registered: 2015-12-02

Posts: 2,000

Re: 10 second questions

---

Actually I never watch Star Wars and not interested in it anyway, but I choose a Yoda card as my avatar in honor of our great friend bobbym who has passed away.
May his adventurous soul rest in peace at heaven.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

Neat work!

#7667. The average of the age of A, B, and C is 25 years, while the average of the age of A, B, and D is 28 years. If D is 28 years old, then what is the age of C?

---

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

#7668. The average age of all employees of M/s XYZ is 35 years. It was later found that age of one of the employees has been taken as 10 years less than his actual age, so the new average after correction increased by 0.5 years. Find the number of employees of M/s XYZ.

---

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,993

Re: 10 second questions

Hi,

#7669. The average of p, q, 13, and 21 is 16 and average of q, 5, 12, and 17 is 10. Find the value of pq.

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.