# RRB Practice Questions | Mathematics – Day-08

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Dear Aspirants,

Mathematics is a complex web. So only most of the applicant’s thought is RRB Mathematics questions are tough to work out. It’s really not, to score the maximum mark in this section you need of regular practice on RRB Maths every day.

Start to practice Quiz for RRB Mathematics section and reveal the answers with detailed explanation. We have taken much care on the explanation part that to understand the RRB Mathematics questions easily. Take RRB Mathematics quiz regularly to perform better on  RRB Maths section without any hurdle.

RRB Exam Mathematics Day – 08

1) The average weight of a group of 8 people increases by 2 kg when one of them weighing 48 kg is replaced by another. The weight of the new person is

a) 64 kg

b) 68 kg

c) 54 kg

d) 80 kg

2) Last year Rohan, Ashok, James, Sam and Pawan all had 42 cars each. This one everyone had sold out 10 cars due some inconveniences. What is the new average at present cars of all of them?

a) 210

b) 32

c) 160

d) 50

3) The ratio of the ages of the mother and the son at present is 3:1. Four years ago the ratio was 4:1. The average age of mother and son 2 years hence will be

a) 35

b) 36

c) 26

d) 24

4) The average salary of P, Q is Rs.5000 and that of R, S and T is Rs.7000. The average salary of all the five people is

a) Rs.7200

b) Rs.6200

c) Rs.6000

d) Rs.1200

5) The average salary of all the 90 employees in an industry is Rs.15000 per month. If the number of permanent staff is twice that of the temporary staff, then the average salary of all temporary employees is

a) Rs.12000

b) Rs.8000

c) Rs.9000

d) Cannot be determined

6) Revanth travels first 1/3rd of the total distance in 20km/hr and the next 1/3rd distance at 60km/hr speed and the last 1/3rd of the distance in 10km/hr speed. The average speed of Revanth is

a) 18km/hr

b) 20km/hr

c) 16km/hr

d) 22km/hr

7) Pavithra started from point A and reached B, which is 200 km apart at the speed of 40km/hr, then she went to C which is 300km away, at a speed of 20km/hr, then she went to D which is 500km away at a speed of 10km/hr. The average speed of Pavithra is

a) 12.258 km/hr

b) 14.55 km/hr

c) 14 2/7 km/hr

d) 13 5/8 km/hr

8) The average presence of employees in an office on First three days of the week is 30 and on last four days are 28. If the average number of employees on all six days is 27, then the number of employees who came to office on Wednesday is

a) 30

b) 20

c) 40

d) 25

9) The average age of five sisters is 42 years. The average age of the last two sisters is 27.5 years and the first two sisters are 55 years. What is the age of the middle sister?

a) 40

b) 32

c) 28

d) 45

10) The average of first 75 even numbers is

a) 55

b) 1001

c) 76

d) 101

The average increases by 2 kg, so the weight is increased by (8×2) =16 kg. So the weight of the new person is (48+16) = 64 kg

Required average = Old average – New average

= 42 – 10 = 32

Let the present ages of mother and son be 3x and x respectively. Four years ago mother’s age and father’s age were (3x – 4) and (x – 4) respectively

(3x – 4) / (x – 4) = 4/1

x = 12 years;

3x = 36 years

At present, average age = 36 + 12 = 48/2 = 24

2 years hence it would be 24 + 2 =26

Average salary = (5000×2 + 7000×3) / (3+2) = Rs.6200

Permanent staff : temporary staff = 2 : 1

Permanent staff = 60

Temporary staff = 30

Total salary = 60 (salary of permanent staff + 30 x salary of temp. Staff)

90 × 15000 = 60k + 30 × I

Here k and l are unknowns. So answer cannot be determined.

Since all the distances are same

Avg speed = 3uvw / (uv + vw + wu)

= (3 × 20 × 60 × 10)/ (1200 + 600 + 200)

=36000/2000 = 18km/hr

Average speed = Total distance / time

= (200 + 300 + 500) / (200/40 + 300/20 + 500/10)

= 1000/70 =100/7 = 14 2/7 km/hr

Average Present employee of first 3 days = 30

Total employee of first 3 days = 90

Average Present employees of last 4 days = 28

Total employees of last 4 d= 112

Sum of six days of employees = 27 × 6 = 162

No of employees on Wednesday = 162 – (90 + 112) = 162 – 112 = 40

Sum of all their ages = 42 × 5 = 210 years

Sum of the first two = 55 × 2 = 110 years

Sum of the last two = 27.5 × 2 = 55 years

Middle sister age = 210 – (110 + 55) = 45 years