Water flows in a tank 150 m × 100 m at the base, through a pipe whose cross-section is 2 dm by 1.5 dm, at the speed of 15 km per hour. In what time will the water be 3 metres deep ?

15 kmph = 15000 m/hour

Water flown in an hour $=frac{2 imes 1.5 imes 15000}{100}$

= 450 cu.metre

Volume of desired water in the tank

= (150 × 100 × 3) cu. metre

$herefore$ Time $=frac{150 imes 100 imes 3}{450}=100$ hours