Question

a tennis player uses up 800 calories every hour. In 1 hour and 15 minutes, how many calories does this player use

Answer 1

15 minutes is 1/4 of an hour. 800 per hour so do 1/4 of that + 800 to get your answer.

Answer 2

Hint:

1 hour = 60 minutes

60 minutes uses up 800 calories
How many calories are used up in 75 minutes?

Make a proportion and solve

\(\Large \frac{60}{800} = \frac{75}{x}\)

cross multiply
\(\Large\frac{a}{b} = \frac{c}{d}\)

then \(\large ad = bc\)