When doing unit rates, do you put pounds or money as the nominator?

What is the value of x in the following equation. -x ^3/2 = -27

Match the scale and the actual area to the area of the corresponding scale drawing. scale: 1 inch to 4 feet actual area: 128 square feet scale: 1 inch to 7 feet actual area: 147 square feet scale: 1 inch to 8 feet actual area: 256 square feet scale: 1 inch to 5 feet actual area: 225 square feet area of scale drawing scale and actual area scale drawing area: 3 square inches arrowright scale drawing area: 8 square inches arrowright scale drawing area: 4 square inches arrowright scale drawing area: 9 square inches arrowright

According to the general equation for conditional probability if p(anb)=3/7 and p(b)=7/8 what is p(a i b)