<span>First, you need to find out how much will the candle cost per volume. If a candle with a volume of 80cm^3 costs $12, the price of the candle per cm^3 would be: $12/80cm^3= $0.15/cm^3
Then the price of a candle with </span>120 cm^3 volume would be:120cm^3* $0.15/cm^3= $18
My suggestion is to look on google, there are plenty of answers and I think it will explain better than me.
I'm really not sure.
Sorry.
4:2 and 2:1 are equivalent ratios to 8:4
Z=kx, 30=8k, so k=30/8=15/4 and z=15x/4, so when x=4, z=15.