a + b = 400 ... .8 a + .8 b = 320
.8 a + .85 b = 400 - 68 = 332
subtracting equations (to eliminate a) ... .05 b = 12
multiplying by ... .85 / .05 ... .85 b = 204
substitute back to find .8 a
The sum of two numbers is 400.If the first number is decreased by 20% and the second number is decreased by 15%, than the sum would be 68 less. Find the numbers after the decrease.
1 answer