1. Suresh drives his car to a place 150 km away at an average speed of 50 km/hr and returns at 30 km/hr. What is his average speed for the whole journey ?

1. 32.5 km/hr.

2. 35 km/hr.

3. 37.5 km/hr

4. 40 km/hr

Answer & Explanation

Answer:- 3

Explanation :-

Average speed = [2xy / (x + y) ] km/hr.

x = 50 kmph.

y = 30 kmph.

Average speed, = [(2 * 50 * 30) / (50 + 30)] = 37.5 km/h.

2. The average age of a husband and his wife was 23 years at the time of their marriage. After five years they have a one year old child. What is the average age of the family ?

1. 21 years

2. 20 years

3. 18 years

4. 19 years

Answer & Explanation

Answer:- 4

Explanation :-

Sum of the present ages of husband, wife and child = (23 * 2 + 5 * 2) + 1 = 57 years.

Average Age of family = (57/3) = 19 years.

3. In an examination, a student’s average marks were 63. If he had obtained 20 more marks for his Geography and 2 more marks for his history, his average would have been 65. How many subjects were there in the examination?

1. 12

2. 11

3. 13

4. 14

Answer & Explanation

Answer:- 2

Explanation :-

Lets assume the number of exams be x.

Therefore,

63x + 20 + 2 = 65x

2x = 22

x = 11.

4. The average salary of all the workers in a workshop is Rs.8000. The average salary of 7 technicians is Rs.12000 and the average salary of the rest is Rs.6000. How many workers are there in the workshop ?

1. 21

2. 22

3. 23

4. 24

Answer & Explanation

Answer:- 1

Explanation :-

Let’s assume the total number of workers be x

Therefore,

8000 x = (12000 * 7) + 6000 (x – 7)

2000x = 42000

x = 21.