Question

A rectangular water tank measures 15m × 6m at top and is 10m deep. It is full of water. If water is drawn out lowering the level by 1 meter,

Answer 1

Your question is incomplete but I can guess what may have been the question....
"We have to find out the final volume of the water tank..."

SOLUTION :

●Initial volume of the water tank( cuboid )
=>
$length \: \times \: breadth \: \times \: height$

=> 15 × 6 × 10
=> 900 cubic meters

●Final volume of the water tank
*(height is decreased by 1m this time)

=> 15 × 6 × 9
=> 810 cubic meters

Therefore, when water is drawn out lowering the level by 1 meter , the volume becomes 810 cubic meters.....

●●●*[plz tell me if the question is different ........
I will try again...]*●●●