Question

He rain caused the river to ride a total of 6 2/3 inches. The river was rising at an average of 2/3 of an inch each hour. How many hours did it rain?

Answer 1

To find out how many hours it rained, divide the total rise in the river by the amount it rose every hour.

$\sf 6\dfrac{2}{3}\div\dfrac{2}{3}$

First convert the mixed number into an improper fraction. We do this by multiplying the denominator to the whole number, adding it to the numerator, which becomes our new numerator, and we keep the denominator the same:

$\sf\dfrac{20}{3}\div\dfrac{2}{3}$

When dividing fractions we flip(the reciprocal) the one we're dividing by and multiply:

$\sf\dfrac{20}{3}\times\dfrac{3}{2}$

Multiply the numerators and denominators together:

$\sf\dfrac{60}{6}$

Simplify by dividing:

$\boxed{\sf 10}$

So it rained for 10 hours.