# 9.10 Revenue and Distance

A factory tests the road performance of new model cars by driving them at two
different rates of speed for at least 100 kilometers at each rate. The speed rates
range from 50 to 70 km/hr in the lower range and from 70 to 90 km/hr in the
higher range. A driver plans to test a car on an available speedway by driving
it for 120 kilometers at a speed in the lower range and then driving 120
kilometers at a rate that is 20 km/hr faster. At what rates should he drive if he
plans to complete the test in 3(1/2) hours?

A train traveled 240 kilometers at a certain speed. When the engine was
replaced by an improved model, the speed was increased by 20 km/hr and the
travel time for the trip was decreased by 1 hour. What was the rate of each
engine?

A merchant bought a number of barrels of apples for 120. He kept two barrels
and sold the remainder at a profit of 2 per barrel making a total profit of 34.
How many barrels did he originally buy?

A clothier bought a lot of suits for 750. He sold all but 3 of them for 864
making a profit of 7 on each suit sold. How many suits did he buy?

The rate of the current in a stream is 3 km/hr. A man rowed upstream for 3 kilometers and then returned. The round trip required 1 hour and 20 minutes. How fast was he rowing?

A number of men subscribed a certain amount to make up a deficit of 100
but 5 men failed to pay and thus increased the share of the others by 1 each.
Find the amount that each man paid.

A man bought a number of articles at equal cost for 500. He sold all but two
for 540 at a profit of 5 for each item. How many articles did he buy?

An athlete plans to row upstream a distance of 2 kilometers and then return
to his starting point in a total time of 2 hours and 20 minutes. If the rate of
the current is 2 km/hr, how fast should he row?

A dealer bought a number of sheep for 440. After 5 had died he sold the
remainder at a profit of 2 each making a profit of 60 for the sheep. How
many sheep did he originally purchase?

A merchant bought some pieces of silk for 900. Had he bought 3 pieces more
for the same money, he would have paid 15 less for each piece. Find the
number of pieces purchased.