Question

21 men take 15 days to construct a 9 m high wall. The numbers of men required to construct
a similar wall which is 8 m high in 7 days are?​

Answer 1

Step-by-step explanation:

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Answer 2

SOLUTION:-

As they given that ,

• 21 men take 15 days to construct a wall of 9m
• x men take 7 days to construct a wall of 8m

As we have to find the no.of men we need So, we find relation between men , days and men , work

If no.of men are increasing then no.of days will decrease that means If more people are there The worl can complete in less days

So,

Men and days are indirect proportional

If more men are there they can construct a wall more that means men are increasing and work also can complete more

Men and work are direct proportional

Men and days

21 : x = 1/15/7

21 :x = 7:15

Men and work

21 : x = 9:8

Now we find compound ratio of 21:x = 7:15 and 21:x and 9:8

21 : x = 7(9) : 15(8)

21:x = 63:120

Product of extremes = Product of means

63(x) = 21(120)

9x = 3(120)

3x = 120

x = 120/3

x =40

So, 40 men are required to construct a wall 8m in 7days