Basic Maths Mcqs

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 __________ .

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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
Total height = 150 * 50 = 7500 cm.
New average = [7500 – 5 * 146 + 5 * 156 ] / 50 = 151 cm

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?

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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
Average mark scored by all the three boys =
[64/100 (800) + 36/100 (800) + 44/100 (800)] / 3 = 384

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.

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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
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

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?

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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
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

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?

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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
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

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).

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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
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

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?

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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
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

The average height of 35 boys in a class was calculated as 180cm. It has later found that the height of one of the boys in the class was wrongly written as 166 cm whereas his actual height was 106 cm. Find the actual average height of the boys in the class (Round off your answer to two decimal places)?

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The average height of 35 boys in a class was calculated as 180cm. It has later found that the height of one of the boys in the class was wrongly written as 166 cm whereas his actual height was 106 cm. Find the actual average height of the boys in the class (Round off your answer to two decimal places)?

A. 179.29 cm
B. 178.29 cm
C. 179.38 cm
D. 178.39 cm
Explanation:
Calculated average height of 35 boys = 180 cm.
Wrong total height of 35 boys = 180 * 35 cm. This was as a result of an actual height of 106 cm being wrongly written as 166 cm. Correct total height of 35 boys = 180 * 35 cm – 166 cm + 106 cm
= 180 * 35 cm – 166 cm + 106 cm/35 = 180 cm – 60 /35 cm
= 180 cm – 1.71 cm = 178.29 cm

The average age of seven persons sitting in a row facing east is 28 years. If the average age of the first three persons is 21 years and the average age of the last three persons is 34 years, then find the age of the person sitting in the middle of the row?

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The average age of seven persons sitting in a row facing east is 28 years. If the average age of the first three persons is 21 years and the average age of the last three persons is 34 years, then find the age of the person sitting in the middle of the row?

A. 30 Years
B. 31 years
C. 26 years
D. 33 years
Explanation:
Total age seven persons = (28 * 7)years
Total age of the first three persons and the last three persons are (21 * 3) years and (34 * 3) years respectively.
Age of the person sitting in the middle of the row = 28 * 7 – 21 * 3 – 34 * 3 = 196 – 63 – 102 = 31 years

The average runs scored by a batsman in 20 matches is 40. In the next 10 matches the batsman scored an average of 13 runs. Find his average in all the 30 matches?

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The average runs scored by a batsman in 20 matches is 40. In the next 10 matches the batsman scored an average of 13 runs. Find his average in all the 30 matches?

A. 31
B. 29
C. 28
D. 30
Explanation:
Total score of the batsman in 20 matches = 800.
Total score of the batsman in the next 10 matches = 130.
Total score of the batsman in the 30 matches = 930.
Average score of the batsman = 930/30 = 31