Quiz Discussion

10 years ago, the average age of a family of 4 members was 24 years. Two children having been born (with age difference of 2 years), the present average age of the family is again 24 years. Then the present age of the youngest child is:

• 1]

  1 years

• 2]

  2 years

• 3]

  3 years

• 4]

  4 years

The average age of 40 students of class is 18 years. When 20 new students are admitted to the same class, the average age of the students of the class is increased by 6 months. The average age of newly admitted students is ?

• 1] 19 years
• 2] 19 years 6 months
• 3] 20 years
• 4] 20 years 6 months

Find the average of all the numbers between 6 and 34 which are divisible by 5 -

• 1] 18
• 2] 20
• 3] 24
• 4] 30

The average of marks in Mathematics for 5 students was found to do 50. Later, it was discovered that in the case of one student the marks 48 were misread as 84. The correct average is :

• 1] 40.2
• 2] 40.8
• 3] 42.8
• 4] 48.2

The average of two numbers is XY. If one number is X, the other is-

• 1]

  Y/2

• 2]

  Y

• 3]

  2XY - X

• 4]

  X (Y - 1)

The average age of 24 boys and their teacher is 15 years. When the teacher's age is excluded, the average age decreases by 1 year. The age of the teacher is :

• 1] 38 years
• 2] 39 years
• 3] 40 years
• 4] 41 years

The present age of a father is 3 years more than three times the age of his son. Three years hence, father's age will be 10 years more than twice the age of the son. The father's age is :

• 1] 33 years
• 2] 39 years
• 3] 45 years
• 4] 40 years

One-fourth of certain journey is covered at the rate of 25 km/h, one-third at the rate of 30 km/h and the rest at 50 km/h. Find the average speed for the whole journey.

• 1]

  600/53 km/h

• 2]

  1200/53 km/h

• 3]

  1800/53 km/h

• 4]

  1600/53 km/h

• 5]

  None of these

Four years ago, the average age of a family of four persons was 18 years. During this period, a baby was born. Today if the average age of the family is still 18 years, the age of the baby is

• 1] 1.2 years
• 2] 2 years
• 3] 2.5 years
• 4] 3 years

The reduction in the speed of an engine is directly proportional to the square of the number of bogies attached to it. The speed of the train is 100 km/hr when there are 4 bogies and 55 kmph when there are 5 bogies. What is the maximum number of bogies that can be attached to the train so that it can move?

• 1]

  4

• 2]

  5

• 3]

  6

• 4]

  7