Question

A man need 21 days to complete 7/8 of a work, how many mored ays he need to complete the work if the quantum of work is increased by 50℅

Answer 1

Answer:

15 days

Step-by-step explanation:

time = total work / efficiency

Total work is not given but the part work is given.

We need to find total time first.

21 = x * (7/8)

21 * 8/7 = x

x = 24 days

If total work increases by 50%, time will also increase by 50% because efficiency is same.

Increase 24 by 50% = 24 + 12 = 36 days

36 days - 21 days (given in que.) = 15 days

Answer 2

Given,

The number of days in which $\[\frac{7}{8}\]$ work is done$\[ = 21\]$

The quantum of work increased in percentage$\[ = 50\]$

Solution,

Formula used, $\[{\rm{Time = }}\frac{{{\rm{Total}}\,{\rm{workdone}}}}{{{\rm{Efficiency}}}}\]$

Assume that the efficiency of the man is x.

Therefore,

$\[\begin{array}{l} \Rightarrow 21 = x \times \frac{7}{8}\\ \Rightarrow x = \frac{{21 \times 8}}{7}\\ \Rightarrow x = 24\end{array}\]$

Now according to the question,

$\[\begin{array}{l} \Rightarrow 24 + \frac{{50}}{{100}} \times 24\\ \Rightarrow 24 + 12\\ \Rightarrow 36\end{array}\]$

Therefore, the number of days required is

$\[\begin{array}{l} \Rightarrow 36 - 21\\ \Rightarrow 15\end{array}\]$

Hence, the required number of days are $\[15.\]$