A military transport helicopter flies a distance of 120 miles between two bases. If the fl… — Armed Services Vocational Aptitude Battery (ASVAB)

A military transport helicopter flies a distance of $120$ miles between two bases. If the flight takes exactly $40$ minutes, what is the helicopter's average speed in miles per hour?

A
$300$
B
$80$
$180$ Answer
D
$3$

Answer

The helicopter's average speed is

180

miles per hour.

To find the correct speed in miles per hour, the travel time must first be converted to hours. Since

40

minutes is

\frac{40}{60}

\frac{2}{3}

of an hour, dividing the distance of

120

miles by

\frac{2}{3}

of an hour yields

180

miles per hour.

Step-by-Step Solution

Convert the travel time from minutes to hours.

40 \text{ minutes} = \frac{40}{60} \text{ hours} = \frac{2}{3} \text{ hours}

The requested rate is in miles per hour, so the time unit must be converted to hours before calculating.

Set up the rate formula using the distance and the converted time.

r = \frac{120 \text{ miles}}{\frac{2}{3} \text{ hours}}

The formula for finding average speed is rate equals distance divided by time (

r = \frac{d}{t}

Solve for the rate by dividing the whole number by the fraction.

120 \div \frac{2}{3} = 120 \times \frac{3}{2} = \frac{360}{2} = 180 \text{ mph}

Dividing by a fraction is achieved by multiplying by its reciprocal.

Key Concept

Average speed is calculated by dividing total distance by total time (

r = \frac{d}{t}

). When the required rate uses different units than the provided information, a unit conversion must be performed first.

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Topics

More questions from this topic