When purchased for 6.19, after mark up +4.20 = $10.39
Hey mate!
You stuck?
128 is 74% of 172.972973 or 173 rounded
173x .74= 128.02 or 128 rounded
Hope this helps!
The total amount is 15% I think I had this same question but different numbers
C = -840
Isolate C by subtracting 900 on both sides:
C = 60-900
Which then gives u C = -840