If you break it up:
Three-eighths = 3/8
Sixteen times a number, we'll call the unknown number X, so 16X.
Twenty Four = 24
The sum of 16X and 24 = 16X + 24
We want 3/8 of that sum so we put the sum in parenthesis and we get:
Y = 3/8(16X + 24) where Y is the answer youd get if you knew what X was.
Perimeter of rectangle=66
length of rectangle=L
width of rectangle=w
P of a rect.= 2(length)+ 2(width)
66= 2L+2w
if the length is 7in more than the width, then
L=7+w
Now we will substitute 7+w in for L. Here is our new equation:
66=2(7+w) + 2w
Solve for w
66=14+2w+2w
66=14+4w
52=4w
w=13
L=7+13, so L=20
I hooe this is explained well enough
239.99 x 75%(75/100) ~ $180
$180 x 90%(90/100) = $162