Apaste is use to cover a billboard it’s made by mixing the following ingredients 4 parts powder ,three parts water , 2 parts resin and one part hardener .to cover one billboard requires 30 pounds of this paste .how many total pounds of resin are required to cover 4 billboards

The total number of parts to the paste is 4+3+2+1 = 10. Of those, 2 parts are resin. If the "parts" are equal weight, then 2/10 of the weight is resin.

One billboard requires 30 pounds of paste, so 4 billboards will require 4·30 = 120 pounds. If 2/10 of the paste is resin, then (2/10)·(120 pounds) of resin will be required, or 24 pounds of resin.