Math Is Fun Forum

mathxyz

Member

From: Brooklyn, NY

Registered: 2024-02-24

Posts: 1,053

Three Probability Problems

A coin is flipped 5 times. What is the probability of landing on heads 3 out of 5 times?

The probability of rain for the next 3 days is 60 percent. What is the probability of no rain for 2 out of 3 days?

A book has 300 pages. What is the probability of opening and closing the book 4 consecutive times and landing on any page between 100 and 250?

Keep_Relentless

Member

From: Queensland, Australia

Registered: 2024-05-05

Posts: 61

Re: Three Probability Problems

I notice your questions have gotten trickier.

I'll make a start on the first one.

It's useful to consider the number of different ways you could have three heads.
You could have:

HHHTT
HHTHT
HHTTH

HTHHT
HTHTH
HTTHH

THHHT
THHTH
THTHH

TTHHH

That's 10 possibilities... out of how many in total?

K_R

---

"The most incomprehensible thing about the world is that it is comprehensible." -Albert Einstein.

mathxyz

Member

From: Brooklyn, NY

Registered: 2024-02-24

Posts: 1,053

Re: Three Probability Problems

I notice your questions have gotten trickier.

I'll make a start on the first one.

It's useful to consider the number of different ways you could have three heads.
You could have:

HHHTT
HHTHT
HHTTH

HTHHT
HTHTH
HTTHH

THHHT
THHTH
THTHH

TTHHH

That's 10 possibilities... out of how many in total?

K_R

Not my questions at all. Questions come from different online sites.