31.

The average (arithmetic mean) of 3³⁰, 3⁶⁰ and 3⁹⁰ is

• 3²⁷ + 3⁵⁷ + 3⁸⁷

• 3⁶⁰

• 3²⁹+3⁵⁹+3⁸⁹

• 3²⁹+3⁵⁹+3⁸⁹

The average of the largest and smallest 3 digit numbers formed by 0, 2 and 4 would be

• 312

• 213

• 222

• 222

The frequency distribution data is given below. If the average age is 17 years, the value of m is 
Age (in m years) :   8       20       26        29
Number of people:   3        2        m         1

• 1

• 2

• 3

• 3

The average monthly expenditure of a family for the first four months is ₹ 2570, for the next three months ₹ 2490 and for the last five months ₹ 3030. If the family saves ₹ 5320 during the whole year, the average monthly income of the family during the year is

• ₹ 3000

• ₹ 3185

• ₹ 3200

• ₹ 3200

The average of six numbers is 20. If one number is removed, the average becomes 15. What is the number removed?

• 5

• 35

• 112

• 112

After replacing an old member by a new member, it was found that the average age of five members of a club is the same as it was 3 years ago. The difference between the ages of the replaced and the new members is

• 2 years

• 4 years

• 8 years

• 8 years

A man spends ₹ 1800 monthly on an average for the first four months and ₹ 2000 monthly for the next eight months and saves ₹ 5600 a year. His average monthly income is

• ₹ 2000

• ₹ 2200

• ₹ 2400

• ₹ 2400

The arithmetic mean of the following numbers
1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6 and 7, 7, 7, 7, 7, 7, 7, is

• 4

• 5

• 14

• 14

The average of first three numbers is double of the fourth number. If the average of all the four numbers is 12. find the 4th number.

• 16

• 

• 20

• 20

If the average of 6 consecutive even numbers is 25, the difference between the largest and the smallest number is

• 8

• 10

• 12

• 12