Answer :
12x+5=a
12x+25% of 12x=b
25%=14
you and your friend pay the same total, a=b
If a=b,
12x+5=12x+14(12x)
First, you want to simplify.
12x+5=12x+18x
Multiply by 8 on both sides to get rid of those fractions
4x+40=4x+x
Subtract 4x on both sides to find x
40=x
Half of x so 1/2 of x
Answer is 20