Question

Select the equation with the solution x = 25. The equation should have the variable on both sides, a decimal coefficient on the left side, and a decimal anywhere on the right side. One of the decimals should be written in tenths, the other in hundredths.
A. 0.4x − 3 = 0.6x + 2
B. 7x − 12.15 = 6x + 12.85
C. 0.5x − 5 = 0.15x + 2
D. 0.6x − 3 = 0.28x + 5

Answer 1

It isn't A because there isn't a decimal in the hundredths.
It isn't B because it doesn't have a decimal coefficient on the left side: that means it could be C or D, to find out we should find what x is in C:
0.5x-5=0.15x+2
0.5x=0.15x+7
0.35x=7
Divide both sides by 7
0.05x=1
Now multiply both sides by 20:
x=20
That means it must be D, let's make sure:
0.6x-3=0.28x+5
0.6=0.28x+8
0.32x=8
Divide both sides by 8:
0.04x=1
Now multiply both sides by 25:
x=25
So the answer is D

Hope this helps :)