Question

If $18$ pumps can raise $2170$ tonnes of water in $10$ days working $7$ hours a day then in how many days will $16$ pumps raise $1736$ tonnes of water working $9$ hours a day

• A. $6$
• B. $7$
• C. $8$
• D. $9$

Answer 1

The correct option is B $7$

$18$ pumps raise $2170$ tonnes in $10$ days working $7$ hours a day.

In $1$ day they raise $\frac{2170}{10}=217$ tonnes

In $1$ hour they raise $\frac{217}{7}=31$ tonnes.

$1$ pump raises water $=\frac{31}{18}$ tonnes.

Now,

$16$ pumps will raise $=\frac{31}{18}\times 16$ tonnes.

Working $9$ hrs a day they will raise $=\frac{31}{18}\times 16\times 9$ tonnes

Let the number of days be $d$ days.

Thus total $=\frac{31}{18}\times 16\times 9\times d$

$1736=\frac{31}{18}\times 16\times 9\times d$

$\Rightarrow d=1736\times \frac{18}{9\times 16\times 31}=7$ days.