Answer:
35 bowls of mashed potatoes.
Explanation:
To make a bowl of mashed potatoes, the chef uses one-fifth of a potato.
To use up one potato, he will make 5 bowls of mashed potatoes from it:
1 / (1/5) = 5 bowls of mashed potatoes.
With the 7 potatoes he has, he can make 7 x 5 bowls = 35 bowls of mashed potatoes.