Question

Find the height of the water level after $9$ seconds if the water is being poured at a rate of $12$ cubic meters per second into a half-empty rectangular tank with length $5$ meters, width $3$ meters, and height $25$ meters.

• A. $6.0$
• B. $7.2$
• C. $18.5$
• D. $19.7$
• E. The tank will be full and overflowing

Answer 1

Answer: (D)

$19.7$

Volume poured after $9$ seconds is $12\times 9=108$ cubic meters.
$\Rrightarrow 108=5\times 3\times h$

$\Rightarrow h=\frac{36}{5}=7.2$
The tank is already half filled, therefore height of water after $9$ seconds is $\frac{25}{2}+7.2=19.7$.