First of all be more spusific in your question
The probability is 56/100, or 14/25 = 0.56.
These events are not mutually exclusive, meaning they can happen at the same time. This means we use
P(A or B) = P(A) + P(B) - P(A and B)
P(carpool or full time) = P(carpool) + P(full time) - P(carpool & full time)
There are 6+9=15 people out of 100 that carpool.
There are 7+4+30+6=47 people out of 100 that work full time.
There are 6 people out of 100 that carpool and work full time.
This gives us
15/100 + 47/100 - 6/100 = 56/100
The 25 box is a better deal:
The 25 box is about $0.16 per diaper and the 89 is about $0.21/d.
Hope this helps!
The answer is C
By the way, that expression means "n choose k". Hope I helped!
