Four vehicles travelled on a road. What can you deduce from the times that they met?
Brian swims at twice the speed that a river is flowing, downstream
from one moored boat to another and back again, taking 12 minutes
altogether. How long would it have taken him in still water?
At Holborn underground station there is a very long escalator. Two
people are in a hurry and so climb the escalator as it is moving
upwards, thus adding their speed to that of the moving steps. ...
How many steps are there on the escalator?
Fifteen students from Dr Challoner's Grammar School were told to
go to a point 60 miles south. The only transport they could use was
a car, which could only carry 5 students beside the driver
(Thasan). Thasan took the students to their destination in 3 loads.
As he left with the first 5, he ordered the remaining 10 to
commence hiking along the road. He unloaded the first group some
distance from the goal, with orders to hike the rest of the way.
Then he returned until he met the remaining ten, picked up 5 of
them, and took them part of the way along the route while the last
5 continued to walk. Finally he returned, picked up the last group
and drove it the rest of the way. They all arrived at the same
time. The students walked at a rate of 4 miles per hour without any
pause for rest, while the car travelled at a speed of 40 miles per
hour. How much time did the hiking save? (You can ignore the time
spent in picking up and discharging passengers.)