OK the problem is focusing on VOLUME and TIME.. you can set up this problem like this... (v1/t1) x (v2/t2). first we plug in what we know. the first container was filled in 4 minutes so this is our "T1". However we weren't giving the volume of the first container but we were given its dimensions. the volume formula is LxWxH. so we plug in 9x11x12 to get 1188. this is our "V1". the same concept applies for the volume of the aquarium. we have its dimensions so just plug in. 24x25x33 = 19800 this is our "V2". the thing we are left trying to find is T2. so now you can do some cross multiplying and division. (T1xV2)/V1 or (4x19800)/1188 and you get 66.67min or 1h and 6.67mins. and thats how long it took to fill the aquarium.