Let's have all the fractions have the denominator, which is 20.
Andy: 2/20
Emily: 8/20
Parents: 5/20
Let's add all the fractions up.
All four: 15/20
This means, there's 5/20 of the bag left.
5/20 of the bag= 50 cherries.
Since they ate three times of what was left, that means they ate 150 cherries.
150+50=200
That means there were 200 cherries. Let's find how many each person ate and what was left.
Left: 50 cherries
Andy: 20 cherries
Emily: 80 cherries
Parents: 50 cherries
All: 200 cherries.
We need to find how many Andy and Emily ate.
80+20=100 or 2/20+8/20= 1/2×200=100
So, Andy and Emily ate 100 cherries.