Practice Questions on Average

 

01) If average of 20 observations x₁, x₂, ------ x₂₀ is y. then the average of x₁ -101, x₂ -101, x₃ – 101, -----, x₂₀ – 101 is

          a) y - 20

          b) y - 101

          c) 20y

          d) 101y

02) The average of x numbers is y and average of y numbers is x. Then the average of all the numbers taken together is [SSC CHSL DEO & LDC Exam 04/12/2011, Shift I]

          a) (x+y)/2xy

          b) 2xy/(x+y)

          b) (x² + y²)/(x+y)

          d) xy/(x + y)

03) The average of x numbers is y² and the average of y numbers is x². So the average of all the numbers taken together is

          a) (x³ + y³)/(x+y)

          b) xy

          c) (x² + y²)/(x+y)

          d) xy² + yx²

04) There are two groups A and B of a class, consisting of 42 and 28 students respectively. If the average weight of group A is 25 kg and that of group B is 40 kg, find the average weight of the whole class.

          a) 69 kg

          b) 31 kg

          c) 70 kg

          d) 30 kg 05) A library has average number of 510 visitors on Sunday and 240 on other days. The average number of visitors per day in a month of 30 days beginning with Sunday is:

          a) 285

          b) 295

          c) 300

          d) 290

06) The average monthly expenditure of a family is Rs 2,200 during first three months, Rs 2, 550 during next four months and Rs. 3,120 during last five months of the year, If the total savings during the yar was Rs 1,260, what is the average monthly income?

          a) Rs. 1,260

          b) Rs 1, 280

          c) Rs. 2, 805

          d) Rs. 2, 850

07) Find the average of 1.11, 0.01, 0.101, 0.001, 0.11 [SSC MTS Exam 10/03/2013, Shift I]

          a) 0.2664

          b) 0.2554

          c) 0.1264

          d) 0.1164

08) 4 boys and 3 girls spent Rs 120 on the average, of which boys spent Rs 150 on the average. Then the average amount spent by the girls is [SSC MTS Exam 10/03/2013, Shift I]

          a) Rs. 80

          b) Rs. 60

          c) Rs. 90

          d) Rs. 100

09) Six tables and twelve chairs were bought for Rs 7,800. If the average price of a table is Rs 750, then the average price of a chair would be [SSC MTS Exam 17/03/2013, Shift I]

          a) Rs 250

          b) Rs. 275

          c) Rs. 150

          d) Rs. 175

10) Out of 20 boys, 6 are each of 1m 15cm height, 8 are 1m 10cm and rest of 1m 12cm. The average height of all of them is [SSC MTS Exam 17/03/2013, Shift II]

          a) 1 m 12.1 cm

          b) 1 m 21.1 cm

          c) 1 m 21 cm

          d) 1 m 12 cm