Problems on Ages Hard Level

A is twice as old as B, and C is 4 years older than A. Their ages add up to 74. How old is C?

A's age is two-thirds of B's. Six years ago A's age was half of B's age then. How old is A now?

A father is 4 times as old as his son. Five years ago he was 7 times as old. After how many more years will the father be twice as old as the son?

The ages of P, Q and R add up to 70. The ratio of Q's age to R's is 3 : 5, and P is 4 years older than Q. How old is R?

Asked his age, a man replied: "Take my age 3 years hence, multiply it by 3, and subtract 3 times my age 3 years ago – you will get my age." How old is he?

In a family the father is 4 times as old as the son, and the mother is 3 years younger than the father. The three are 87 years old in all. How old is the son?

Ten years ago a mother was 3 times as old as her son. Ten years from now she will be twice as old. What is the ratio of their present ages?

Two people are 70 years old together. The elder is now twice as old as the younger was when the elder was as old as the younger is now. How old is the elder?

A mother and her twin sons are 50 years old in all. In 10 years the mother's age will equal the sum of the sons' ages then. How old is the mother?

The ages of Jay and Kay are in the ratio 6 : 5 and add up to 44. What will be the ratio of their ages after 8 years?