80 goes into 142 once, so one is our whole number. there are still 62 / 80 left, so we reduce this fraction. The answer is
1
15 + .65x = 80
15 + .65x = 80
15 - 15 + .65x = 80 - 15
.65/.65x = 65/.65
x = 100
Beth swam 100 laps.
No, Noah used the diameter instead of the radius in the calculations is the answer.