Question

A cylindrical water tank has a diameter of 14 meters and a height of 20 meters. A water truck can fill TT cubic meters of the tank every minute. How long will it take the water truck to fill the water tank from empty to half full?

• A. $400$ minutes
• B. $375$ minutes
• C. $490$ minutes
• D. $380$ minutes

Answer 1

The correct option is C $490$ minutes

490 minutes, or 8 hours and 10 minutes: First find the volume of the cylindrical tank:

$v=\pi r^2\times h$

$=\pi (7{)}^2\times 20$

$=980\pi$

If the water truck can fill n cubic meters of the tank every minute, it will take 980 minutes to fill the tank completely; therefore, it will take $980÷2=490$ minutes to fill the tank halfway.