BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

please help. thanks.

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 37
Joined: Sat May 24, 2008 8:59 pm

please help. thanks.

by silvia928 » Mon Jun 02, 2008 10:20 am
For one toss of a certain coin, the probability that the outcome is heads is 0.6. If thus coin is tosse 5 times, which of the following is the probability that the outcome will be heads at least 4 times?

Ans . 5(0.6)^4(0.4)+(0.6)^5
Top
Source: — Problem Solving |
Master | Next Rank: 500 Posts
Posts: 438
Joined: Mon Feb 12, 2007 9:44 am
Thanked: 26 times

by chidcguy » Mon Jun 02, 2008 11:42 am
Atleast 4 times is 4times or 5 times

Probability is the probability of getting heads 4 times + probability of getting heads 5 times

Probability of Tail + Probability of head =1

probability of tail = 1-.06 =0.4

probability of getting heads 5 times = (0.6) ^5

probability of getting heads 4 times = probability of getting heads 4 times X probability of getting tails once

= (.6)^4 X (.4)

This can happen in 5 ways HHHHT, THHHH, HHTHH and so on

So it is 5 X (.6)^4 X (.4)
Top
Post new topic Post Reply
• Page 1 of 1