Answer :
18 inches cost 90 cents
The porportion is inches / cents = 18/90
For 15 inches of wire: 15/x, where x is the cost of 15 inches of wires in cents.
So, equal both:
18/90 =15/x
Solve for x:
x = 15 / (18/90)
x= 75 cents
18 inches cost 90 cents
The porportion is inches / cents = 18/90
For 15 inches of wire: 15/x, where x is the cost of 15 inches of wires in cents.
So, equal both:
18/90 =15/x
Solve for x:
x = 15 / (18/90)
x= 75 cents