John ' s age is 42 years and Kelvin ' s age is 26 years and how many years ago was Kelvin ' s age half of John ' s age ? 

Out of 100 families in the neighbourhood, 50 members have radios , 75 members have TVs and 25 members have VCRs . Only 10 families have all three and each VCR owner also has a TV . If some families have radio only , how many have only TV ? 

In the following question, correct the equation by interchanging two numbers.
9 × 3 – 8 ÷ 2 + 7 = 26

If “P” denotes “divided by”, “R” denotes “added to”, “S” denotes “subtracted from” and “Q” denotes “multiplied by”, then
48 P 4 R 3 Q 4 S 6 Q 4 = ?

If “*” denotes “added to”, “&” denotes “divided by”, “@” denotes “multiplied by” and “%” denotes “subtracted from”, then
399 & 19 @ 21 % 41 * 100 =?

If “@” denotes “added to”, “#” denotes “multiplied by”, “®” denotes “divided by” and “%” denotes “subtracted from”, then which of the following equation is true?

The weights of 4 boxes are 30, 40, 50 and 80 kilograms. Which of the following cannot be the total weight, in kilograms, of any combination of these boxes and in a combination a box can be used only once?

The sum of the ages of Arjun and his daughter is 48. The average of the ages of Arjun, his daughter and his son is 25. What is the age of Arjun’s son?