Question

36 boys can do a piece of of work in 49 days how many extra boys should be engaged so that the work may be finish in 21 day​

Answer 1

Answer:

48 boys

Step-by-step explanation:

step 1

work out the total number of days to complete the piece of work. Each boy worked 49 days and there were 36 boys

Days*Boys = total number of days

49*36= 1764

so it took total of 1764 days to complete the piece of work

step2

days*boys = total number of days

we get

21*boys= 1764

boys = 1764/21= 84

so 84 boys needed to finished a piece of work in 21 days

step 3

84-36=48

48 extra boys are required to complete the piece of work

Answer 2

$\sf\red{We\: can\:apply \:chain \:rule \:for \: this\:problem}$

$\sf\orange{Direct\:Porportion=36(boys)49(days)}$

$\sf\orange{Indirect\:Proportion=x(boys)21(days)}$

$\sf\pink{So, 36 × 49 = x × 21}$

$\sf\pink{x = \frac{(36 \times 49)}{21}}$

$\sf\blue{x=84\:boys \: should\: be\: there\:for \:the \:completion\: of\:work.}$

$\sf\blue{But\:we \:already \: have\:36 }$

$\sf\blue{So, 84 - 36 = 48\: boys \:are\: needed}$