Quiz Discussion

Out of 20 boys, 6 are each of 1 m 15 cm height, 8 are of 1 m 10 cm and rest of 1 m 12 cm. The average height of all of them is :

• 1] 1 m 12.1 cm
• 2] 1 m 21.1 cm
• 3] 1 m 21 cm
• 4] 1 m 12 cm

If the arithmetic mean of 0, 5, 4, 3 is a, that of -1, 0, 1, 5, 4, 3 is b and that of 5, 4, 3 is c, then the relation between a, b, and c is

• 1] a = b = c
• 2] a : b : c = 3 : 2 : 4
• 3] 4a = 5b = c
• 4] a + b + c = 12

The average age of students of a class is 15.8 years. The average age of boys in the class is 16.4 years and that of the girls is 15.4 years. The ratio of the number of boys to the number of girls in the class is-

• 1] 1 : 2
• 2] 2 : 3
• 3] 3 : 4
• 4] 3 : 5

Find the average of the first 40 natural numbers.

• 1]

  21

• 2]

  20.5

• 3]

  21.5

• 4]

  None Of These

When the average age of a couple and their son was 42 years, the son married and got a child after one year. When the child was 5 years old, the average age of the family became 36 years. What was the age of daughter-in- law at the time of their marriage ?

• 1] 23 years
• 2] 24 years
• 3] 25 years
• 4] 26 years

Five years ago, the average age of A, B, C and D was 45 yr. with E joining them now, the average of all the five is 49 yr. How old is E?

• 1] 25 years
• 2] 40 years
• 3] 45 years
• 4] 64 years

The average weight of 8 men is increased by 1.5 kg when one of the men, who weight 65 kg is replaced by a new man. The weight of the new man is-

• 1] 70 kg
• 2] 74 kg
• 3] 76 kg
• 4] 77 kg

There are two sections A and B of a class, consisting of 36 and 44 students' respectively. If the average weight of section A is 40kg and that of section B is 35kg, find the average weight of the whole class.

• 1] 30 kg
• 2] 35 kg
• 3] 42.5 kg
• 4] 37.25 kg

Average of a, b, and c is 11; average of c, d and e is 17; average of e and f is 22 and average of e and c is 17. Find out the average of a, b, c, d, e and f.

• 1]

  \(15\frac{2}{3}\)

• 2]

  \(18\frac{1}{2}\)

• 3]

  \(16\frac{1}{2}\)

• 4]

  None of these

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)