Question

ada bought 80 feet of wire for 16.80. she need 20 more feet. if the unit price is the same, how much would she pay for the extra 20 feet of wire

Answer 1

The unit price is obtained as follows:

$\frac{16.80\text{ \ }}{80\text{ ft of wire}}=0.21\frac{\text{ \ }}{\text{ ft of wire}}$

Then, 20 ft of wire cost:

$20\text{ ft of wire}\cdot0.21\frac{\text{ \ }}{\text{ ft of wire}}=4.2\text{ \ }$

She would pay $4.2 for the extra 20 feet of wire​