Question

It takes 7 men 7 hours to build 7 bicycle. How many hours does it take for 21 men to build 21 bicycle? (2 marks)

Answer 1

7 men build 7 bicycle in 7 hours.

1 man builds 7 bicycle in 7 x 7 or 49 hours.

1 man builds 1 bicycle in $\frac{49}{7}$ or 7 hours.
(1 mark)

21 men build 1 bicycle in $\frac{7}{21}$ hours.

21 men build 21 bicycle in $\frac{7\times 21}{21}$ hours = 7 hours.
(1 mark)