Distance between -4 and -3 is 1 and there is no distance between 0
If $36 is 3/4 of the total cost, then you can divide 36 by 3 to get the answer for what 1/4 of the cost is. 36 divided by 3 is 12. 12 times 4 is 48. the cost is $48.
I believe that this would be representative.
Silver = 10%
Gold = 90%
Amount of gold to be deducted
90/100 × 18 = 16.2 g
75/100 × 18 = 13.5
16.2 - 13.5 = 2.7
Amount o silver to added.
2.7 × 5 = 13.5
Answer = 13.5 g
