Question

Mailyn loves cookies. She can eat 32 in an hour. Her brother Juan, however, needs 3 hours to eat the same amount of cookies. How long will it take them to eat 40 cookies together?

Answer 1

we know that

1) Mailyn can eat 32 cookies in an hour

1 hour  is equal to 60 minutes

Find how cookies eats Mailyn in one minute

by proportion

$\frac{32}{60} \frac{cookies}{minutes}= \frac{x}{1} \frac{cookie}{minutes} \\\\ x=32/60\\x=0.53 \ cookies$

2) Juan needs 3 hours to eat 32 cookies

Find how cookies eats Juan in one minute

by proportion

$\frac{32}{180} \frac{cookies}{minutes}= \frac{x}{1} \frac{cookie}{minutes} \\\\x=32/180 \\x=0.18\ cookies$

3) Find how long will it take them to eat 40 cookies together

we know that

Maylin and Juan eats in one minute together ---------> (0.53+0.18)=0.71 cookies

so

by proportion

$\frac{0.71}{1} \frac{cookies}{minutes}= \frac{40}{x} \frac{cookie}{minutes} \\\\0.71*x=40\\x=56.34 \ minutes$

therefore

the answer is

$56.34\ minutes$