if x is the bigger num and y is the smaller
x + y = 91
x - 3y = 7.7
multiply by -1
x+y = 91
-x + 3y = -7.7
add the equations
4y = 91 - 7.7
4y = 83.3
y = 20.825
then x+y = 91 use to find x
x+20.825 = 91
x = 70.175
the two numbers are 70.175 and 20.825
it is 10% because 10 percent got better in the experiment
I think the answer is D not to sure
