If the pth , qth and rth terms of an a. p be a, b,c respectively, then show that a (q-r)+b (r-p)+c(p-q)=0

Which problem would you use the following proportion to solve for? 24/x=40/100 a. what is 40% of 24? b. what percent is 24 of 40? c. twenty-four is 40% of what number? d. forty percent of 24 is what number?