AMC12每日一题(2000年真题#04)

2000 AMC 12竞赛试题/第4题

Problem

Each day, Jenny ate 20% of the jellybeans that were in her jar at the beginning of that day. At the end of the second day, remained. How many jellybeans were in the jar originally?

                     (A)  40    (B)  50    (C)  55    (D)  60    (E)  75

Solution

Since Jenny eats 20% of her jelly beans per day, 80%=4/5 of her jelly beans remain after one day.

Let be the number of jelly beans in the jar originally.