61. What same number should be added to each of the numbers 2, 7, 10, 25 so that they may be in proportion?
62. A father is 7 times as old as his son. Two years ago, the father was 13 times as old as his son. What is the present age of son?
63. A number subtracted thrice a number is 8 then the number is
64. Two number are in the ratio 3: 8. If the sum of the numbers is 165, then its difference divided by 15 is
61. 3 should be added to each of the numbers to make them in proportion: 5, 10, 13, 28.
62. The present age of the son is 10 years old.
63. The number is 4.
64. The difference divided by 15 is 5.