Question

A music store gives every 20th customer a $5 gift card. every 50th customer gets a $10 gift card. Which customer will be the first to receive both types of gift cards?

Answer 1

basically

when wiill the customer be 20th and 50th
or what number is both a multiplule of 50 and 20

the answer is 100
20=2*2*5
50=2*5*5
2*2*5*5=100
100th customer gets both