There are 20 coupons rolled up and placed inside round plast

There are 20 coupons rolled up and placed inside round plastic balls in a box. There are 3 different types of coupons: 10 of them can be redeemed for “free drinks”, 5 can be redeemed for “free desserts”, and 5 can be redeemed for “free entrees”. If you shake the box and then randomly select one coupon. What’s the probability that you will get a free entree coupon?

Solution

P(free entry cooupon) = 5/20 = 0.25