Luke took the same number of vitamin pills each day. After 3 days, he had 4/5 of the pills left. After another 5 days, he had 21 pills left. How many pills did he have at first?

Answer 1

P - 3x = 4P/5

P/5 = 3x

P = 15x

P -8x = 21

15x - 8x = 21

7x = 21

x = 3 pills per day

P= 15(3) = 45 pills originally