Average Mcqs - Set 5

1)   The total marks obtained by a student in Mathematics and Physics is 60 and his score in Chemistry is 20 marks more than that in Physics. Find the average marks scored in Mathematics and Chemistry together.

a. 40
b. 30
c. 25
d. Data inadequate
Answer  Explanation 

ANSWER: 40

Explanation:
Let the marks obtained by the student in Mathematics, Physics and Chemistry be M, P and C respectively.

Given , M + C = 60 and C – P = 20 M + C / 2 = [(M + P) + (C – P)] / 2 = (60 + 20) / 2 = 40

2)   Five years ago the average of the ages of A and B was 40 years and now the average of the ages of B and C is 48 years. What will be the age of the B ten years hence?

a. 55 years
b. 56 years
c. 58 years
d. Data inadequate
Answer  Explanation 

ANSWER: Data inadequate

Explanation:
Let the present ages of A, B and C be a, b and c respectively.

Given, [(a – 5) + (b – 5)] / 2 = 40 => a + b = 90 — (1)
(b + c)/2 = 48 => b + c = 96 — (2)
From (1) and (2), we cannot find b

3)   Aftab bought 65 books for Rs.1150 from one shop and 50 books for Rs.920 from another. What is the average price he paid per book ?

a. Rs.20
b. Rs.18
c. Rs.22
d. Rs.16
Answer  Explanation 

ANSWER: Rs.18

Explanation:
Average price per book = (1150 + 920) / (65 + 50) = 2070 / 115 = Rs.18

4)   The average height of 50 pupils in a class is 150 cm. Five of them whose height is 146 cm, leave the class and five others whose average height is 156 cm, join. The new average height of the pupils of the class (in cm) is __________ .

a. 149
b. 151
c. 152
d. 153
Answer  Explanation 

ANSWER: 151

Explanation:
Total height = 150 * 50 = 7500 cm.

New average = [7500 – 5 * 146 + 5 * 156 ] / 50 = 151 cm

5)   In an exam, Amir scored 64 percent, Masood scored 36 percent and asif 44 percent. The maximum score awarded in the exam is 800. Find the average mark scored by all the three boys?

a. 384
b. 364
c. 324
d. 404
Answer  Explanation 

ANSWER: 384

Explanation:
Average mark scored by all the three boys =

[64/100 (800) + 36/100 (800) + 44/100 (800)] / 3 = 384

6)   The average mark of the students of a class in a particular exam is 80. If 5 students whose average mark in that exam is 40 are excluded, the average mark of the remaining will be 90. Find the number of students who wrote the exam.

a. 20
b. 15
c. 25
d. 35
Answer  Explanation 

ANSWER: 25

Explanation:
Let the number of students who wrote the exam be x.

Total marks of students = 80 x.
Total marks of (x – 5) students = 90(x – 5)
80x – (5 * 40) = 90(x – 5)
250 = 10x => x = 25

7)   A student scored an average of 80 marks in 3 subjects: Physics, Chemistry and Mathematics. If the average marks in Physics and Mathematics is 90 and that in Physics and Chemistry is 70, what are the marks in Physics?

a. 60
b. 64
c. 72
d. 80
Answer  Explanation 

ANSWER: 80

Explanation:
Given M + P + C = 80 * 3 = 240 — (1)

M + P = 90 * 2 = 180 — (2)
P + C = 70 * 2 = 140 — (3)
Where M, P and C are marks obtained by the student in Mathematics, Physics and Chemistry.
P = (2) + (3) – (1) = 180 + 140 – 240 = 80

8)   The average of four positive integers is 69. The highest integer is 93 and the least integer is 39. The difference between the remaining two integers is 28. Which of the following integers is the higher of the remaining two integers?

a. 58
b. 86
c. 49
d. None of these
Answer  Explanation 

ANSWER: 86

Explanation:
Let the four integers be A, B, C and D where A > B > C > D.

(A + B + C + D)/4 = 69 => A + B + C + D = 276 —> (1)
A = 93, D = 39 and B – C = 28
(1) => B + C = 276 – (A + D) = 276 – 132 = 144.
B + B -28 = 144
B = (144 + 28)/2 = 86

9)   The present average age of a family of five members is 26 years. If the present age of the youngest member in the family is ten years, then what was the average age of the family at the time of the birth of the youngest member ? (Assume no death occurred in the family since the birth of the youngest).

a. 18 years
b. 14 years
c. 20 years
d. 16 years
Answer  Explanation 

ANSWER: 20 years

Explanation:
Present total age of the members = 26(5) = 130 years.

Present age of the youngest member = 10 years
Present total age of the remaining four members = 130 -10 = 120 years
Their average age at the time of the birth of the youngest member = [120 – (4 * 10)] / 4 = 30 – 10 = 20 years

10)   The total marks obtained by a student in Physics, Chemistry and Mathematics is 150 more than the marks obtained by him in Physics. What is the average mark obtained by him in Chemistry and Mathematics?

a. 75
b. 150
c. 50
d. None of these
Answer  Explanation 

ANSWER: 75

Explanation:
Let the marks obtained by the student in Physics, Chemistry and Mathematics be P, C and M respectively.

P + C + M = 150 + P
C + M = 150
Average mark obtained by the student in Chemistry and Mathematics = (C + M)/2 = 150/2 = 75

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