Question

12 men can build a wall in 15 days. They work for 3 days and then the contractor brings a team of 18 men to complete the work. How many days will they now take to complete the remaining work? ​

Answer 1

Step-by-step explanation:

The time taken by 18 men to build the remaining wall is 8 days .

Step-by-step explanation:

Given as :

Let The 18 man can build the remaining wall in d days

Time taken by 12 men to build a wall = 15 days

i.e 12 men in 15 days make 1 wall

Or, 12 men in 1 day make \dfrac{1}{15}

15

1

wall

∴, 12 men in 3 days make \dfrac{1}{15}

15

1

× 3 wall

i.e 12 men in 3 days make \dfrac{1}{5}

5

1

wall

Again

Contractor bring team of 18 men to complete the remaining work

Remaining work = 1 - \dfrac{1}{5}

5

1

Or, Remaining work = \dfrac{5-1}{5}

5

5−1

∴ Remaining work = \dfrac{4}{5}

5

4

Now,

∵ \dfrac{men\times day}{work}

work

men×day

= constant

So, \dfrac{12\times 3}{\frac{1}{5}}

5

1

12×3

= \dfrac{18\times d}{\frac{4}{5}}

5

4

18×d

Or, 4 × 12 × 3 = 18 × d

∴, d = \dfrac{144}{18}

18

144

i.e d = 8 days

So, The time taken by 18 men to build the remaining wall = d = 8 days