10 second questions

Jai Ganesh · 2010-08-19 22:05:29

Hi bobbym,

The answers to 2320 are correct. Remarkable!

#2321. The top and bottom of a tower were seen to be at angles of depression 30 degrees and 60 degrees from the top of a hill of height 100 meters. Find the height of the tower.

#2322.

bobbym · 2010-08-19 22:44:39

Hi ganesh;

Jai Ganesh · 2010-08-20 01:11:57

Hi bobbym,

Both 2321 and 2322 are correct. Thanks for the neat sketch. Excellence!

#2323. Find the square root of

.

#2324. The perimeter of a rectangle is 32 cm and its area is 48 sq.cm. Find its length and breadth.

JaneFairfax · 2010-08-20 02:00:36

#2325. Evaluate the following infinite sum:

Last edited by JaneFairfax (2010-08-20 04:23:08)

bobbym · 2010-08-20 02:52:16

JaneFairfax · 2010-08-20 04:24:17

bobbym · 2010-08-20 04:48:06

Enjoyed it Jane!

ganesh wrote:

Thanks for the neat sketch.

Thanks for saying that but I am using a new program geogebra and don't yet have it under control. I have always preferred numerical work and tended to scoff at geometry. Hating it like it was group theory. But lately there have been several geometric construction type problems here and I found them interesting to work on. This is my favoritte:

http://www.mathisfunforum.com/viewtopic … 91#p148391

Geogebra because it dynamically computes lengths, angles, areas in real time solved the problem quickly. Reducing my algebra to just a show.

JaneFairfax · 2010-08-20 06:03:05

bobbym wrote:

Hating it like it was group theory.

bobbym · 2010-08-20 21:38:11

JFF wrote:

Yes, but I am fond of the people who do it.

Jai Ganesh · 2010-08-21 01:51:51

Hi bobbym, JaneFairfax,

The solutions 2323, 2324 are perfect. Stupendous!

Welcome back JaneFairFax!

#2326. If the slant height and diameter of a conical tomb are 25 m and 14 m respectively, find the volume of the conical tomb.

#2327. The area of the base right circular cone is 78.5 sq.m. If its height is 12 m find its volume.

#2328. The volume of a cone is the same as that of cylinder whose height is 9 cm and diameter 40 cm. Find the radius of the base of the cone if its height is 108 cm.

#2329. Given
A = {-8,-7,-5,1,2,4}
B = {-7,1,3,4,5,6}
C = {-8,-5,2,4,6,7} verify

#2330. Given
A = {-9,-7,-6,-3,0,2}
B = {-7,-3,0,4,5,6}
C = {-9,-6,2,-7,8}

bobbym · 2010-08-21 07:23:04

ganesh wrote:

Welcome back JaneFairFax!

Agreed. The thought of once again being able to interact with the legendary JFF has me ecstatic as well!

Hi ganesh;

Jai Ganesh · 2010-08-21 15:57:44

Hi bobbym,

The replies 2326, 2327, 2328, and 2329 are on the dot. Superb!

I wonder why you had not included 2330 in the replies!

#2331. If

= {1,2,3,4,5,6,7,8},
A = {2,4,5,7},
B = {2,5,6,8},
prove that

.

#2332. Find the value of m if (f) o (g) = (g) o (f), when f(x)=3x+m, g(x)=4x+3.

#2333. If the area of a triangle, whose vertices are (1,3), (-7,k), (5,-1) is 10 sq.units, find k.

#2334. Find the equation of the straight line joining the point (3,2) and the point of intersection of the straight lines 2x+3y=23 and 2x-y=3.

bobbym · 2010-08-21 16:23:58

Hi ganesh;

I wonder why you had not included 2330 in the replies!

Ran out of energy!

Jai Ganesh · 2010-08-21 23:05:38

Hi bobbym,

All the solutions are perfectly right. Great going!

#2335. A tooth-paste company interviewed 141 people in a city. It was found out that 90 use Brand A paste, 80 use Brand B paste, 50 use Brand C paste, 40 use both A and B, 28 use both B and C, 26 use both C and A, and 15 use all these three pastes. Find how many use
(i) A and B and not C
(ii) B only and
(iii) C and A and not B.

#2336. Find the value of

#2337. Find the value of

#2338. Find the value of

bobbym · 2010-08-22 01:15:07

Hi ganesh;

Jai Ganesh · 2010-08-22 16:38:21

Hi bobbym,

The replies to 2336, 2337, and 2338 are perfect. Brilliant!

Regarding 2335, I get
(i) No. of people who are A and B and not C : 25 people
(ii) No. of people who use only B : 27 people.
(iii) No. of people who use C and A and not B : 11 people.

#2339. Two dice are thrown. What is the probability of getting odd number in the first die or the total of the numbers on the face as 7?

#2340. A person stands at a distance of 50 meters from a building and observes the top and the bottom of a flag pole on the building at angles of elevation 60 degrees and 45 degrees. Find the heights of the building and the flag pole.

#2341.

= {5,6,9,11,13,17,18},
A = {6,13,17,19}
and B = {5,9,17}; find
.

#2342. Given

with domain {-3,0}. Find the range of f.

bobbym · 2010-08-22 17:42:46

Hi ganesh;

#2335. A tooth-paste company interviewed 141 people in a city. It was found out that 90 use Brand A paste, 80 use Brand B paste, 50 use Brand C paste, 40 use both A and B, 28 use both B and C, 26 use both C and A, and 15 use all these three pastes. Find how many use
(i) A and B and not C
(ii) B only and
(iii) C and A and not B.

This is what I did for 2335, where did I go wrong?

For i)

90 + 80 - 26 - 28 + 15 = 131

For iii)

90 + 50 - 40 - 28 + 15 = 87

bobbym · 2010-08-22 18:21:39

Hi ganesh;

Continuing with the quiz!

Jai Ganesh · 2010-08-23 01:47:27

Hi bobbym,

Regarding 2339, the solution given by you is perfectly correct! Magnificent!

The error crept in by oversight. My apology!

The replies 2340, 2341, and 2342 are perfect.

#2343. If A = {2,4,8}, B = {1,2,6,8},C = {1,5,6,8}, then verify

#2344. If A = {a,b,c,d,e,f,g,h}, B = {a,b,e,f}, and C = {a,c,e,g,h}, find

.

bobbym · 2010-08-23 01:56:03

Hi ganesh;

No problem! I make enough mistakes to know how is easy it is to go wrong.

Jai Ganesh · 2010-08-24 01:15:08

Hi bobbym,

The solutions given to 2343 and 2344 are precise. Excellent!

#2345. If the angle of depression of a stone on the ground form the top of a building is 60 degrees. If the stone is at a distance of 50 meters away from the building, find the height of the building.

#2346. Find the Least Common Multiple of x[sup]2[/sup]-x-12 and x[sup]2[/sup]-9x+20.

#2347. Simplify:

PS: Time given for 2347 is 3 minutes.

bobbym · 2010-08-24 12:18:02

Hi ganesh;

JaneFairfax · 2010-08-25 00:50:29

ganesh wrote:

Welcome back JaneFairFax!

bobbym wrote:

The thought of once again being able to interact with the legendary JFF has me ecstatic as well!

Thanks guys! Its nice to feel welcome.

#2348. Without using long division, short division, calculator, computer program, Microsoft Excel or any other form of software or technology, calculate 35999999/5999 mentally.

bobbym · 2010-08-25 01:04:21

Jai Ganesh · 2010-08-25 02:29:33

Hi bobbym,

The answers to 2345, 2346, 2347 are correct. Keep it up!

Since the problem by JaneFairfax and reply by btobbym, I continue.

#2349. If

and are the roots of the equation
3x[sup]2[/sup]-5x+2=0, find the value of

Math Is Fun Forum

#1626 2010-08-19 22:05:29

Re: 10 second questions

#1627 2010-08-19 22:44:39

Re: 10 second questions

#1628 2010-08-20 01:11:57

Re: 10 second questions

#1629 2010-08-20 02:00:36

Re: 10 second questions

#1630 2010-08-20 02:52:16

Re: 10 second questions

#1631 2010-08-20 04:24:17

Re: 10 second questions

#1632 2010-08-20 04:48:06

Re: 10 second questions

#1633 2010-08-20 06:03:05

Re: 10 second questions

#1634 2010-08-20 21:38:11

Re: 10 second questions

#1635 2010-08-21 01:51:51

Re: 10 second questions

#1636 2010-08-21 07:23:04

Re: 10 second questions

#1637 2010-08-21 15:57:44

Re: 10 second questions

#1638 2010-08-21 16:23:58

Re: 10 second questions

#1639 2010-08-21 23:05:38

Re: 10 second questions

#1640 2010-08-22 01:15:07

Re: 10 second questions

#1641 2010-08-22 16:38:21

Re: 10 second questions

#1642 2010-08-22 17:42:46

Re: 10 second questions

#1643 2010-08-22 18:21:39

Re: 10 second questions

#1644 2010-08-23 01:47:27

Re: 10 second questions

#1645 2010-08-23 01:56:03

Re: 10 second questions

#1646 2010-08-24 01:15:08

Re: 10 second questions

#1647 2010-08-24 12:18:02

Re: 10 second questions

#1648 2010-08-25 00:50:29

Re: 10 second questions

#1649 2010-08-25 01:04:21

Re: 10 second questions

#1650 2010-08-25 02:29:33

Re: 10 second questions

Board footer