Step - 1: Finding number of work units for the first case . {\textbf{Step - 1: Finding number of work units for the
first case}}{\text{.}} Step - 1: Finding number of work units for the first case .
Total 36 men work for a total of 18 days to complete it. {\text{Total 36 men work
for a total of 18 days to complete it}}{\text{.}} Total 36 men work for a total of 18 days to complete it .
So total work units = 36 × 18 = 648 {\text{So total work
units}} = 36 \times 18 = 648 So total work units = 36 × 18 = 648
Thus, for the first case ,it’s a total of 648 work units. {\text{Thus, for the first
case ,it's a total of 648 work units}}{\text{.}} Thus, for the first case ,it’s a total of 648 work units .
Step - 2: Finding number of days for the second case . {\textbf{Step - 2: Finding number of days for the second
case}}{\text{.}} Step - 2: Finding number of days for the second case .
Let it takes x days for the workers to complete the task,so we can write {\text{Let it takes
}}x{\text{ days for the workers to complete the task,so we can write}} Let it takes x days for the workers to complete the task,so we can write
Number of work units = 27 × x = 27 x {\text{Number of work
units}} = 27 \times x = 27x Number of work units = 27 × x = 27 x
Also, the work is same so the work units must be same {\text{Also, the work is
same so the work units must be same}} Also, the work is same so the work units must be same
So, equating the work units for the two cases, we get {\text{So, equating the
work units for the two cases, we get}} So, equating the work units for the two cases, we get
648 = 27 x 648 = 27x 648 = 27 x
x = 648 27 = 24 x = \dfrac{{648}}{{27}}
= 24 x = 27 648 = 24
Hence option D is correct {\textbf{Hence option D is correct}} Hence option D is correct