Question 260314
The original area is 20x 16 = 320
The new area is to be 320*.60 = 192
we get
{{{(20-x)(16-x) = 192}}}
By foil, we get
{{{x^2 - 36x + 320 = 192}}}
setting = 0 we get
{{{x^2 - 36x +128= 0}}}
{{{(x-32)(x-4)=0}}}
x = 32 cm
or
x = 4 cm.
x = 4 cm is our answer.