| A boy and girl together fill a cistern with water. The boy pours 4 L of water every 3 min and the girl pours 3 L every 4 min. How much time will it take to fill 100 L of water in the cistern? [SSC (CGL) 2008] |
A) 36 min
B) 42 min
C) 48 min
D) 44 min
Correct Answer: C
Solution :
| Quantity of cistern filled by boy in 1 min \[=\frac{4}{3}L\] |
| Quantity of cistern filled by girl in 1 min \[=\frac{3}{4}L\] |
| Quantity of cistern together in 1 min |
| \[=\left( \frac{4}{3}+\frac{3}{4} \right)=\frac{16+9}{12}=\frac{25}{12}L\] |
| Now, \[\frac{25}{12}L\]of water is filled in 1 min. |
| \[\therefore \]100 L of water is filled in \[\left( \frac{12}{25}\times 100 \right)=48\min \] |
You need to login to perform this action.
You will be redirected in
3 sec
