Divide the number of times she picked a color by the total times she picked a pen:
Red = 6/30 reduces to 1/5
Blue = 10/30 reduces to 1/3
Black = 14/30 reduces to 7/15
The probability of picking a blue pen , then a red pen is found by multiplying the two possibilities together:
1/3 x 1/5 = 1/15
There is a 1/15 probability.
The answer is 72+12n
Hope it has helped you
