6 gallons in 4 1/2 seconds to travel 1/4 mile
Multiply through by 4
-------
The dragster will :
use 24 gallons in 18 seconds to travel 1 mile.
A=12
120% of a =80% of b
120%a = 80%b
120a/100 = 80b/100
Divide through by 100
120a = 80b
Divide through by 80
120a/80 = b
But a=12
120x 12/80 = b
18 = b
b = 18
a+b = 12 + 18 = 30
2(x+2) = 60
x+2 = 30
x = 28
The correct answer is C
The dimensions are factors of the expression
... you multiply them together to get the area
the factors are ... (x - 7) & (x + 2)