Question

If 35 workers can build a house in 16 days, then it takes---------- days for 28 workers working at the same rate to build the same house. (2 marks)

Answer 1

Let 28 workers can build a house in x days.

According to the question

35 workers can build a house in 16 days
Then 28 workers can build a house in x days
(1 mark)
Hence

By the principle of inverse proportion, we have
$35\times 16=28\times x$

$x=\frac{35\times 16}{28}$
x = 20

Therefore, 28 workers can build a house in 20 days
(1 mark)