Question

A speed limit of 100 kilometers per hour (kph) is approximately equal to 62 miles per hour (mph). Write an equation relating kilometers per hour, k, to miles per hour, m. Then predict the following measures. Round to the nearest tenth.

a) a speed limit in mph for a speed limut of 75 kph

b) a speed limit in kph for a speed limit of 20 mph

Answer 1

1.) 75 x .62 = 46.5 I multiplied by .62 because the kph to mph ratio is 1:.62
2.) 20 x 1.6 = 32 I multiplied by 1.6 because that's how many km are in a mile.

Answer 2

75 kmph = 46.5 mph

20 kmph = 12.4 mph

Explanation:

100 kilometers per hour = 62 miles per hour

1 kmph = 0.62 mph

k kmph = 0.62k miles per hour

Where k denotes the speed in kmph

a) a speed limit in mph for a speed limit of 75 kph

k kmph = 0.62k

75 kmph =
`0.62 * 75 = 46.5`

75 kmph = 46.5 mph

b) a speed limit in kph for a speed limit of 20 mph

k kmph = 0.62k

20 kmph =
`0.62 * 20 = 12.4`

20 kmph = 12.4 mph