What are the outcomes favorable to event A?

Question

You pick a whole number between 1 and 100. If A is the event that the number you picked is divisible by 3 and 7, what are the outcomes favorable to event A?

Answer 1

a number that is divisible by 3 and divisible by 7 also must be divisible by the product 3*7=21

what numbers between 1 and 100  are multiples of 21 ?

21, 42, 63, 84 are the favorable outcomes

P(A)=4/100=1/25