Answer is 3/5 of the pizza
Step by step
We know she ate 1/3 of a pizza, that leaves 2/3 left over
We know she ate 2/5 of the 2/3 left overs
So
2/5 x 2/3 = 4/15 she ate as a snack
Add this to the 1/3 she ate for lunch
1/3 + 4/15 = total pizza she ate
To add these, we need the denominator the same
1/3 = x/15, we multiply the 3 x 5 to get 15 so we do the same to the numerator, 1 x 5 = 5
So 5/15 + 4/15 = 9/15
We can simplify this to 3/5
Problem solved
