The image below displays that the water leakage happens from the bottom of the trough at a constant rate. 2hrs later, the level of the water has fallen by 20cm. How many more mins will it take for the trough to empty completely?

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Answer 1 · 2018-05-30T14:53:20

$1.4$ $1.4$ hours more

$V = 30 \times ((40 \times \frac{80 + 120}{2}) + 120 \times 20) = 122400$ $V = 30 times ( ( 40 times (80+120)/2 ) + 120 times 20) = 122400$ cubic cm

Leakage rate $\frac{30 \times 120 \times 20}{2} = 36000$ ${ 30 times 120 times 20 } / { 2 } = 36000$ cubic cm per hr

$\frac{122400}{36000} - 2 = 1.4$ $122400/ 36000 -2 = 1.4$ hours more to leak out