Question

There are 5 red pens,3 blue pens and 2 green pens in a box. Gary takes at random a pen from the box and gives the pen to his friend. Gary then takes at random another pen from the box . work out the probability that both pens are the same colour.

please help​

Answer 1

♫ - - - - - - - - - - - - - - - ~Hello There!~ - - - - - - - - - - - - - - - ♫

➷ Find the total number of pens:

5 + 3 + 2 = 10

The probability of taking a red the first time is 5/10

The probability of taking a blue the first time is 3/10

The probability of taking a green the first time is 2/10

If you want to take the same colored pen again, there would be 1 less of the total pen (as it hasn't been replaced) and there would be one less of that color (as one has already been taken)

Therefore:

The probability of taking a red again is 4/9

The probability of taking a blue again is 2/9

The probability of taking a green again is 1/9

Multiply the values for the same color together:

5/10 x 4/9 = 20/90

3/10 x 2/9 = 6/90

2/10 x 1/9 = 2/90

Add these values together:

20/90 + 6/90 + 2/90 = 28/90

Your answer is 28/90

✽

➶ Hope This Helps You!

➶ Good Luck (:

➶ Have A Great Day ^-^

↬ ʜᴀɴɴᴀʜ ♡