Question : $A$ varies directly as $(B+18)$ and $A=108$ when $B=36$. Find the value of $A$ when $B=68$.

Question : The sum of three numbers is 126. If the ratio of the first to third is 3 : 7 and that of the second to third is 4 : 7, then what is the second number?

Question : In three positive numbers, the ratio of first and second is 3 : 4 and the ratio of second and third is 3 : 5. The product of first and third is 4500. What is the sum of the three numbers?

Question : The sum of the three numbers is 540. The ratio of second to third is 9 : 13 and that of first to third is 2 : 7. The third number is: