Swimming pool

[jnbimmer]

What is the rate, in cubic meters per minute, at which water is flowing into a particular rectangular swimming pool?

(1) The volume of the swimming pool is 420 cubic meters.

(2) The surface level of the water is rising at the rate of 0.5 meters per minute.

[neoreaves]

r = ? (m^3/min)


Pool = Rectangular

1) V = 420 m^3

Insufficient as it doesn't say anything about the rate ...we could be pouring in at any rate into the pool ...the volume doesnt matter

2) Surface level increase = 0.5 m / min

we only know about the surface level increase ...the volume of the pool can be anything ..so Insufficient

C) we know the volume and rate of surface level increase

however, imagine this

v = 420 m^3 and height is 1 m then surface area of the pool will be 420 and the rate will be 420(0.5)/min = 210 m^3/min

but if height = 2m then Surface area will be 210 and the rate will be 210(0.5)/min = 105 m^3/min

Thus IMO Answer should be E

[Fiver]

Agree with E.
Rate of flow = total volume/total time

With both combined also, the total time is going to be twice the height.
There are several numbers that the height and the other dimensions could take to form a product of 420.

[jnbimmer]

Answer is E. Thanks all