Quant: Average part 2

1.A student was asked to find the arithmetic mean of the following 12 numbers:
  3,11,7,9,15,13,8,19,17,21,14,x
  He found the mean to be 12. The value of x will be:
  (a) 3 (b)7
  (c)17 (d)31
  (e) none of these

2.The avg marks of 50 students in a class is 72. The avg marks of boys and girls in that subject are 70    and 75 respectively. The number of boys in the class is
   a)20 b) 25
   c)35 d) 30
   e) none of these

3. The avg wt of A, B, C is 45 kg. If the avg wt of A and B be 40 kg and that of        B and C be 43         kg, then the wt of B is
    a) 20 b) 31
    3) 26 d) 17
    e) none of these

4. There are 100 students in 3 sections A B and C of a class. The avg marks of all the three section of     the class is 84.
   The avg of B and C is 87.5 and the avg marks of A is 70. The no. of students in A was
   a) 30 b) 35
   c) 20 d) 25
   e) 48

5. The avg of 20 numbers is 15 and the avg of first 5 is 12. The avg of rest is
   a) 16 b) 15
   c) 14 d) 13
   e) none of these

6. Out of 4 no. the avg of the first three is 16 and last three is 15. If the last no is 20. then the first           number is
    a) 23 b) 25
    c) 28 d) 21
    e) none of these

7. The avg of six no is 3.95. The avg of two of them is 3.4, while the avg of the other 2 is 3.85. The         avg of the remaining two number is
    a) 4.6 b) 4.5
    c) 4.8 d) 4.7
    e) 4.9

8. The avg of 6 no is 20. If one no is removed the avg becomes 15. What is the no removed.
   a) 5 b) 35
   c) 112         d) 42
   e) none of these

9. The avg of 50 no is 38. If two numbers, namely 45 and 55 are removed, the avg of the remaining         numbers is
    a) 37.5 b) 37.9
    c) 36.5 d) 37.0
    e) none of theses

10.A batsman scores 87 runs in his 17th inning and thus increased his avg by 3. Find the avg after           17th innings.
    a) 39 b) 87
    c) 90 d) 84
    e) none of these


Answers:
1) b
2) d
3) b
4) c
5) a
6) a
7) a
8) e
9) c
10) a

Solutions will be provided soon