the width of a square-based storage tank is 3m less than its height. The tank has a capacity of 20m^3. If the dimensions are integer values in metres, what are they?
math - Reiny, Thursday, October 13, 2011 at 7:23pm
each side of base --- x m
height --- x+3
x^2(x+3) = 20
x^3 + 3x^2 = 20
since the solution is to be an integer, try
x=1 , 1 + 3 = 20 , no
x=2, 8 + 3(4) = 20 ,YES
well, that was easy.
base is 2 m by 2, with a height of 5
math - justme, Thursday, October 13, 2011 at 7:32pm
but its less than 3
math - Reiny, Thursday, October 13, 2011 at 7:39pm
base is 2 m by 2 m
height is 2+3 = 5 m
volume = 2x2x5 = 20
My answer is correct.
what do you mean by "but its less than 3"
math - justme, Thursday, October 13, 2011 at 7:56pm
oh nothing , i get it now, thank you :)