Probability that both pens will be blue = 1/10
Step-by-step explanation:
Number of blue pens = 2
Number of black pens = 3
Total pens = 2 + 3 = 5
Probability of chosing a blue pen = number of blue pen/total pens
Probability of chosing a blue pen = 2/5
The first pen was picked without being replaced, then the second pen was picked:
This means the number of blue pens after the first pick will reduce by 1
Number of blue pens after the first pick = 2 - 1 = 1
The total number of pens will also reduce by 1 after the first pick:
Total pens after the first pick = 5 - 1 = 4
Probability that both pens will be blue = Probability (1st blue and 2nd blue)
Probability (1st blue) = 2/5
Probability (2nd blue) = 1/4
'and' means multiplication
Probability of both pen to be blue = 2/5 × 1/4 = 2/20
Probability that both pens will be blue = 1/10