7.1. Pasha and Sasha made three identical toy cars. Sasha made a third of the first car, a fifth of the second car, and a fifteenth of the third car. What part of the entire work did Sasha do?
Answer: one fifth

Solution 1: In total, Sasha made $1 / 3+1 / 5+1 / 15=3 / 5$ of a car. This constitutes $3 / 5: 3=1 / 5$ of three cars.

Solution 2: Divide each car into 15 parts. In total, there are 45 parts. Sasha made five parts of the first car, 3 parts of the second car, and 1 part of the third car. That is, a total of 9 parts out of 45, in other words, one fifth.

Criteria: Only the answer - 0 points. Partial solution of the problem - 0 points.