Andrew drove from his house to his sister's house in 8 hours at an average of 60 miles per hour. on the way home he drove at an average rate of 64 miles per hour. how long did it take him to drive home?

It took him 7.5 hrs to drive home.

Step-by-step explanation:

The distance is the same, going or returning.

Recall that distance = rate times time.

Here, distance from Andrew's to his sister's is (60 mph)(8 hr) = 480 mi

If distance = rate times time, then time = distance / rate.

Here we have time = 480 mi / 64 mph = 7.5 hrs

It took him 7.5 hrs to drive home.

cut 138 centimeters off

step-by-step explanation:

250-112 = 138

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4