February 2021

A Metra commuter train leaves
Union Station in Chicago at 12 noon. Two hours later, an
Amtrak train leaves on the same track, traveling at an
average speed that is 50 miles per hour faster than the
Metra train. At 3 PM the Amtrak train is 10 miles behind the
commuter train. How fast is each going?

A life raft, set adrift from a sinking ship
150 miles offshore, travels directly toward a Coast Guard
station at the rate of 5 miles per hour. At the time that the
raft is set adrift, a rescue helicopter is dispatched from
the Coast Guard station. If the helicopter’s average speed is
90 miles per hour, how long will it take the helicopter to
reach the life raft?

An 8-horsepower (hp) pump can fill a
tank in 8 hours. A smaller, 3-hp pump fills the same tank in
12 hours. The pumps are used together to begin filling this
tank. After four hours, the 8-hp pump breaks down. How
long will it take the smaller pump to fill the tank?

Two pumps of different sizes, working
together, can empty a fuel tank in 5 hours.The larger pump
can empty this tank in 4 hours less than the smaller one. If the
larger pump is out of order, how long will it take the smaller
one to do the job alone?

On a recent flight from Phoenix to Kansas
City, a distance of 919 nautical miles, the plane arrived
20 minutes early.On leaving the aircraft, I asked the captain,
“What was our tail wind?”He replied, “I don’t know, but our
ground speed was 550 knots.” How can you determine if
enough information is provided to find the tail wind? If possible,
find the tail wind. (1 knot = 1 nautical mile per hour)

An air rescue plane averages
300 miles per hour in still air. It carries enough fuel for 5
hours of flying time. If, upon takeoff, it encounters a head
wind of 30 mi/hr, how far can it fly and return safely?
(Assume that the wind remains constant.)

A sugar molecule has twice
as many atoms of hydrogen as it does oxygen and one more
atom of carbon than oxygen. If a sugar molecule has a
total of 45 atoms, how many are oxygen? How many are
hydrogen?

The speed of a moving walkway is
typically about 2.5 feet per second. Walking on such a
moving walkway, it takes Karen a total of 40 seconds to
travel 50 feet with the movement of the walkway and then
back again against the movement of the walkway.What is
Karen’s normal walking speed?

A motorboat maintained a
constant speed of 15 miles per hour relative to the water in
going 10 miles upstream and then returning. The total time
for the trip was 1.5 hours. Use this information to find the
speed of the current.

Ans: 5 mi/hr.
Any solution for this? Thanks