Mom’s car drove 72 miles in 90 minutes. there are 5,280 feet per mile. how fast did she drive in feet per second? a.0.8 feet per secondb.48.9 feet per second c. 0.009 feet per secondd. 70.4 feet per second explain how ?

d. Mom drove at a rate of 70.4 feet per second

Step-by-step explanation:

This is a problem of proportions.

Mom drove 72 miles over a span of 90 minutes

(72 miles) / (90 minutes)

If there are 5,280 feet in a mile, and 60 seconds in a minute, we can solve for her speed in feet per second by multiplying ratios

( 72 miles) / (90 minutes) * (5,280 feet) / (1 mile) * (1 minute) / (60 seconds)

Our numerator is then

(72 miles * 5,280 feet * 1 minute) = 380,160 miles*feet*minute

Our denominator is then

(90 minutes * 1 mile * 60 seconds) = (5,400 minutes*miles*seconds)

Giving us

(380,160 miles*feet*minutes) / (5,400 minutes*miles*seconds)

380,160 / 5,400 = 70.4

Miles and minutes cancel out, leaving us with units

feet / second

So

Mom drove at a rate of 70.4 feet per second

answer: c.  

step-by-step explanation:

mixtures containing substances that get attracted to magnet can be separated using a magnet. we can separate iron from a mixture of sand and iron, as only iron attracts to the magnet.