The sum of two numbers is 405 and their ratio is 8 : 7. Find the numbers.

The ages of A and B are in the ratio 7 : 5. Ten years hence, the ratio of their ages will be 9 : 7. Find their present ages.

The difference between the squares of two consecutive numbers is 31. Find the numbers.

Find a number such that when 5 is subtracted from 5 times the number, the result is 4 more than twice the number.