The number of students in three classes are in the ratio 2:3:5. If the number of students in each class is increased by 20 the ratio become 4: 5: 7. The total number of students before the increase was

If a : b = 20:5 then find out the value of (13a-9b): (11a-7b)?

What must be added to two numbers that are in the ratio of 3:4, so that they become in the ratio 4:5?

Rs. 425 is divided among 4 men, 5 women and 6 boys such that the share of a man , a woman and a boy may be ratio of 9:8:4. What is the share of a woman?

Find the forth proportional to $${ x^{2}b^{2}c^{3}}$$, $${ x^{3}bc^{4}}$$ and $${ x^{4}b^{2}c^{2}}$$.

Two numbers are in the ratio of 3: 5. If 9 be subtracted from each, then they are in the ratio of 12: 23. Find the numbers. 

In a factory men, women and children were employed in the ratio 8:5:1 to finish a job and their individual wages were in the ratio 5:2:3. Total daily wages of all amount to Rs. 318. Find the total daily wages paid to each category.

The third proportional of two numbers 4 and 20 is