Question

Pita has 12 coins in her bag there are three 1 pound coins and nine 50p coins she takes 3 coins out of the bag at random, work out the probability she takes out exactly £2.50 as a fraction

Answer 1

27/220.

Explanation:

To get £2.50 Pita has to take two pound coins and one 50p coin.

The probability of picking £1 then £1 then 50 p = 3/12 * 2/11* 9/10

= 9/220.

The number of possible arrangements of 2 pounds and 1 50p

= £-£-50, £-50-£ and 50-£-£.

= 3

So the required probability = 3 * 9/220

= 27/220.