model 1 basic average questions Section-Wise Topic Notes With Detailed Explanation And Example Questions

Question : 1

If average of 20 observations $x_1 , x_2 , ....., x_20$ is y, then the average of $x_1 – 101, x_2 – 101, x_3 – 101, ....., x_20 –101$ is

a) 20y

b) 101y

c) y – 101

d) y – 20

Question : 2

The average weight of 8 persons increases by 2.5 kg when a new person comes in place of one of them weighing 65 kg. The weight of the new person is

a) 76 kg

b) 76.5 kg

c) 85 kg

d) 84 kg

Question : 3

The average marks of 32 boys of section A of class X is 60 whereas the average marks of 40 boys of section B of class X is 33. The average marks for both the sections combined together is

a) 46$1/2$

b) 45$1/2$

c) 45

d) 44

Question : 4

The average weight of 3 men A, B and C is 84 kg. Another man D joins the group and the average now becomes 80 kg. If another man E whose weight is 3 kg more then that of D, replaces A, then the average weight of B, C, D and E becomes 79 kg. Then weight of A is

a) 75 kg.

b) 76 kg.

c) 74 kg.

d) 72 kg.

Question : 5

The average of 1, 3, 5, 7, 9, 11, -------- to 25 terms is

a) 625

b) 50

c) 25

d) 125

Question : 6

The average income of 40 persons is Rs. 4200 and that of another 35 persons is Rs. 4000. The average income of the whole group is :

a) Rs.4106$2/3$

b) Rs.4108$1/3$

c) Rs.4106$1/3$

d) Rs.4100