Question

20 men can build a wall in 9 days then how long would it take 12 men to build the same wall

Answer 1

$\begin{array}{|c||c|}\cline{1-1}\cline{2-2}\textbf{No.of workers}&\textbf{No. of days}\cline{1-2}\cline{2-2}20&9\\12&x\cline{1-2}\cline{2-2}\end{array}$

$\text{As number of workers decreaes, number of days increases}$

$\therefore\textbf{It is inverse variation}$

$\text{Since it is inverse variation, we have to apply "straight multiplication"}$

$\implies\,20{\times}9=12{\times}x$

$\implies\,x=\dfrac{20{\times}9}{12}$

$\implies\,x=\dfrac{5{\times}9}{3}$

$\implies\,x=5{\times}3$

$\implies\boxed{\bf\,x=15}$

$\therefore\textbf{15 days are required to build the same wall by 12 men}$

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Answer 2

Answer:

15 days.

Step-by-step explanation:

=20×9=12× x

=x=15