The bakery has a full tray of brownies. One customer comes in and buys 1/4 of the tray. The next customer buys 1/5 of what remained in the tray. How much did they buy and how much remains in the tray?

Answer 1

1/4 + 1/5

Find the common denominators, change to equivalent fractions, and add these two numbers.

Then subtract from 20/20.