Darts

Jason threw some darts at this board. Every dart landed on the board.

Jason scored exactly 100.

How many darts did he throw?

Which numbers did they land on?

Age 13-16

A bicycle made for two

Harry, Mary and Zed want to get to a party 8 miles away. They can walk on average at 4mph and they have a bicycle for two that they can ride at an average speed of 20mph.

They all set out at the same time. Zed starts walking. Harry and Mary ride a certain distance on the bicycle. Mary then gets off and continues on foot, while Harry returns to pick up Zed. All three of them arrive at the party at the same time.

After how many miles did Mary get off the bicycle and start walking?

How long did she take to get to the party?

Brainteaser solutions

from page 38

Darts: Jason threw six darts; four landed on 17 and two on 16.

A bicycle made for two:

Mary rides for 6 miles. They all arrive at the party after 48 minutes.

Hints: Mary and Zed arrive at the same time, so must ride and walk the same distances. M is the point where Mary starts walking and Z is the point where Zed starts riding. Harry travels the middle leg ZM three times. The time that he takes to ride 2a+3b miles must equal the time Mary takes to ride a+b miles then walk a miles.