Question

If 8 workers can build a wall in 10 days, then in many days the given number of workers will complete the same work.
4 workers
2 workers
5 workers
10 workers (5 marks)

Answer 1

Since time and number of workers follow inverse proportion for same work, we have
$\text{Time}\times \text{Number of workers}=Constant$
(1 mark)

$\text{Let the number of days be}x$
$\text{in each case}$

Case (1) :

$8\times 10=$ $x\times 4$
$\Rightarrow x=20$
(1 mark)
Case (2) :

$8\times 10=$ $x\times 2$
$\Rightarrow x=40$
(1 mark)
Case (3) :

$8\times 10=$ $x\times 5$
$\Rightarrow x=16$
(1 mark)
Case (4) :

$8\times 10=$ $x\times 10$
$\Rightarrow x=8$
(1 marks)