In: Statistics and Probability
A bag contains 10 Cherry Starbursts and 20 other flavored
Starburts. 7 Starbursts are chosen randomly without
replacement.
Find the probability that 4 of the Starbursts drawn are cherry.
Solution:
Probability of an event E is defined as follows:
P(E) = no. of favourable outcomes/total number of outcomes
We have a bag that contains 10 Cherry Starbursts and 20 other flavored Starbursts. 7 Starbursts are choosen randomly without replacement and we have to find the probability that 4 of the Starbursts drawn are cherry. If 4 Starbursts are cherry then remaining 3 drawn Starbursts will be other flavoured.
Total number of ways of selecting 4 cherry Starbursts from 10 cherry Starbursts is,
Total number of ways of selecting 3 other flavoured Starbursts from 20 other flavoured Starbursts is,
Total number of ways in which 4 of the Starbursts drawn are cherry when the total 7 Starbursts are drawn is
Total number of ways of selecting 7 Starbursts from 30 Starbursts is,
Hence, probability that 4 of the Starbursts drawn are cherry is,
The probability that 4 of the Starbursts drawn are cherry is 0.1176.