it is given that the ratio of gas to oil in the mixture is ,
gas : oil
40 : 1
also we have 3 ounce of oil,
so multiply the the ratio by 3
gas : oil
40 x 3 : 1 x 3
120 : 3
so, for 3 ounce of oil we need 120 ounces of gas.
thus, the answer is 120 ounce of oil