Bunuel
What is the perimeter, in meters, of a rectangular playground 24 meters wide that has the same area as a rectangular playground 64 meters long and 48 meters wide?
(A) 112
(B) 152
(C) 224
(D) 256
(E) 304
Find area of first playground to find its perimeter.
For area of the first playground, use the doubling and halving rule to find the length of the first rectangular playground.*
Areas of the two playgrounds are equal:
\((24)(L_1) = (48)(64)\)
W = 24 is half of W = 48. If one factor is halved, the other is doubled. \(L_1 = (2*64) = 128\). OR
\(L_1 = \frac{(48)(64)}{24} = (64 * 2) = 128\)
Perimeter of first playground: 2(24 + 128) = 304
Answer E
*You could also factor to avoid long calculations:
\((24)(L_1) = (48)(64)\)
\([(3)(8)](L_1) = [(6)(8)][(8)(8)]\)
Factor out 8 on both sides. Isolate L on LHS by dividing 6 by 3 = 2. Then L = (2)(8)(8) = 128