Dear Readers, Important Aptitude Questions for Railway / SSC / FCI Exam was given here with solutions, candidates those who are preparing for those exams can use this material.

**1).**The average age of four brother is 12 yr. If the age of their mother is also included. The average is increased by 5 yr. The age of mother (in yr) is

a)
37

b)
43

c)
48

d)
53

**2).**The average of marks of 14 students calculated as 71. But it was later found that the marks of one student had been wrongly entered as 42 instead of 56 and of another as 74 instead of 32. The correct average is

a)
67

b)
68

c)
69

d)
71

**3).**Out of seven given numbers, the average of the first four numbers is 4 and that of the last four numbers is also 4. If the average of all the seven numbers is 3, fourth number is

a)
3

b)
4

c)
7

d)
11

**4).**The average of 100 number is 44. The average of these 100 numbers and 4 other new number is 50. The average of the four new numbers will be

a)
800

b)
200

c)
176

d)
24

**5).**The average of 6 observations is 45.5. If one new observation is added to the previous observations, then the new average becomes 47. The new observation is

a)
58

b)
56

c)
50

d)
46

**6).**A man covers half of his journey at 6 km / h and the remaining half at 3 km / h. His average speed is

a)
9 km / h

b)
4.5 km / h

c)
4 km / h

d)
3 km / h

**7).**A boy went out from a group of eight boys. A new boy comes at his place whose weight is 56 kg. The average weight of the group increases by 2.5, then what is the average weight of the boys?

a)
38.5

b)
38

c)
36.5

d)
36

**8).**The average of first 10 even numbers is

a)
10

b)
12.5

c)
9

d)
11

**9).**A car travelled from station A to station B at a speed of v

_{1}km / h and travelled back from B to A at v

_{2}km / h. What is the average speed of the car?

a)
[ (1 / v

_{1}) + (1 / v_{2}) ] / 2
b)
(v

_{1}+ v_{2}) / 2
c)
2v

_{1}v_{2}/ (v_{1}+ v_{2})
d)
2(v

_{1}+ v_{2}) / v_{1}v_{2}**10).**The average of 5 numbers is 7. When 3 numbers are added, the average of the eight numbers is 8.5 the average of three new number is

a)
11

b)
7.75

c)
8.5

d)
7

__Answers__**:**

**1). a) 2). c) 3). d) 4). b) 5). b) 6). c) 7). d) 8). d) 9). c) 10). a)**

__Solution:__

**1).**Total age of 4 brothers = 48 yr

Total age of 4 brothers and their mother = 17 ×
5 = 85 yr

The age of mother = 85 – 48 = 37 yr

**Answer: a)**

**2).**Total marks of 14 students = 14 × 71 = 994

New total marks of students = 994 – 42 – 74 +
56 + 32 = 966

New average of marks = 996 / 14 = 69

**Answer: c)**

**3).**Fourth number

=
(4 × 4 + 4 × 4 – 3 × 7)

=
(16 + 16 – 21)

=
(32 – 21) = 11

**Answer: d)**

**4).**Sum of 4 new numbers = 50 × 104 – 100 × 44

=
5200 – 4400 = 800

Average = 800 / 4 = 200

**Answer: b)**

**5).**Let the new observations be x, then

(x + 6 × 455) / 7 = 47

x + 273 = 47 × 7 = 329

x = 329 – 273 = 56

**Answer: b)**

**6).**If the same distances are covered at different speeds of x km / h and y km / h, the average speed of the whole journey is given by

=
(2xy) / (x + y) km / h

Required average speed = (2 × 6 × 3) / (6 + 3)
= 36 / 9 = 4 km / h

**Answer: c)**

**7).**Average weight of boys = x kg

Average weight increase after new boy = 2.5 kg

(x + 2.5) × 8 = x × 7 + 56

8x + 20 = 7x + 56

8x – 7x = 56 – 20

x = 36

**Answer: d)**

**8).**Required average = (1 / 10) (2 + 4 + 6 + 8 + …. + 18 + 20)

=
(2 / 10) (1 + 2 + 3 + 4 + …. + 9 + 10)

=
(2 / 10) × [ (10 × 11) / 2 ] = 11

**Answer: d)**

**9).**Let distance between station A and B be S km then

Average speed of car = Distance covered /
total time

=
{ (S + S) km / [ (S / v

_{1}) + (S / v_{2}) ] } h
=
2S / { S [ (1 / v

_{1}) + (1 / v_{2}) ] }
=
2 / [ (v

_{2}+ v_{1}) / (v_{1}v_{2}) ]
=
2 v

_{1}v_{2 }/ (v_{1}+ v_{2})**Answer: c)**

**10).**Average = (85 × 8 – 5 × 7) / 3 = (68 – 35) / 3

=
33 / 3 = 11

**Answer: a)**

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