Question

A remote control helicopter travels 2/5 of a mile in 1/10 of a hour. What is it’s speed in miles per hour

Answer 1

speed = 4 mph

Explanation:

The best way to do this is to convert the fractions into decimals.

2/5 = 0.4 miles

1/10 = 0.1 hours

Answer: speed = 0.4 /0.1 = 4 miles per hour.

Put this into your calculator

.4

÷

.1

=

The answer should come out as 4.

You can do this with fractions but it will drive you a little batty.

`((2)/(5) )/((1)/(10))=(2)/(5)*(10)/(1)=(2*10)/(5*1) =\text{4}`

Notice that the second set of fractions multiplys 2/5 * 10/1. That's because you invert and multiply the bottom fraction.