# Aptitude - Averages Online Quiz

Following quiz provides Multiple Choice Questions (MCQs) related to Averages. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using Show Answer button. You can use Next Quiz button to check new set of questions in the quiz.

Q 1 - N2 is the average of m numbers and that of n number is m2, find the average of (m+n) numbers is ?

A - m-n

B - m+n

C - m/n

D - mn

### Explanation

```Total of (m+n)  numbers = (mn2+nm2)= mn(m+n)
Average of numbers( m+n) = mn(m+n)/ (m+n) = mn```

Q 2 - 45 kg weight is the average of A, B and C. if the given condition of weight is 40 kg is the average of A and B while B and C have the average weight is 43 kg. Find out the weight of B?

A - 123 kg

B - 84 kg

C - 31 kg

D - 65 kg

### Explanation

```A, B and C have total weight = 45*3 = 135 kg
A and B  have total weight =    40*2 = 80 kg
B and C have total weight = 43*2 = 86 kg
∴ weight of B = (80+86- 135) = 31 kg.```

Q 3 - 38.6°C is the average temperature of 4 first day of the week while 40.3°C is the average of last 4 days in a week. Find out the temperature on Thursday if 39.1°C is average of whole week?

A - 23°

B - 45°

C - 41.9°

D - 50°

### Explanation

```M+T+W+Th = (38.6*4)= 154.4 ...(i)
T+W+Th+F = (40.3*4) =161.2 ...(ii)
M+T+W+Th+F+S+Su =(39.1*7) =273.7 ...(iii)
(i)+(ii) –(iii) we find that ,  (154.4+161.2- 272.7) =41.9°C
∴ 41.9 °C was the temperature on Thursday.```

Q 4 - 84 kg is the average weight of 3 people A, B and C. 80 kg is the average if D joins the group. A new man E replaces who have 3kg more weight than D. At that time 79 kg is the average weight of B, C, D and E. What should be the weight of A?

A - 75 kg

B - 34 kg

C - 26 kg

D - 56 kg

### Explanation

```A+B+C= (3*84)= 252 kg.     A+B+C+D= (4*80)= 320 kg
weight of D =( 320- 252) =68 kg.   weight of E = (68+3)= 71 kg.
sum of the weight of B+C+D+E= (79*4)= 316 kg ,
sum of the weight of B+C+D = (316-71)=245kg.
Total weight of A = (320- 245 )= 75 kg.```

Q 5 - What should be the largest number if first number is the half of the second number and third number is 1/3 of the second number? 44 is the average of three numbers?

A - 72

B - 62

C - 52

D - 42

### Explanation

```if x is the third number , then second number = 3x  ∴ first number = 3x/2
Average =1/3 (3x/2+3x+x) ⇒  (11x/6) =44  ⇒ 11x=264 ⇒ x = 24
Hence, the second number (24*3)=72  is the largest number.```

Q 6 - M is the average of 5 consecutive natural numbers. What should be the improvement in average if next 3 numbers included?

A - 1

B - 1.5

C - 1.4

D - 2

### Explanation

```let the 5 consecutive natural numbers be n, n+1,n+2, n+3, n+4. Then
n+(n+1)+(n+2)+(n+3)+(n+4) /5 = 5n+10= 5m ⇒ 5(n+2)= 5m  ⇒ (n+2) =m ⇒ n=(m-2)
New numbers are m-2, m-1, m, m+1,m+2,m +3, m+4, m+5
New average = ( 8m+12)/8 = m+1.5 , which is 1.5 more than m.```

Q 7 - The average age of 35 students in class is 16 years. The average age of 21 students is 14. What is the average age of remaining 14 students?

A - 18 years

B - 19 years

C - 17 years

D - 15 years

Explanation

```Sum of the ages of 14 students = (16 x 35) - (14 x 21) = 560 - 294 = 266
Therefore Required average = 266⁄14 = 19years.
```

Q 8 - The mean of 50 observation was 36. It was found later that an observation 48 was wrongly taken as 23. The corrected new mean is?

A - 36.5

B - 39.1

C - 36.1

D - 35.2

Explanation

```Correct sum = (36 x 50 + 48 - 23) = 1825.
Therefore Correct Mean = 1825⁄50 = 36.5.
```

Q 9 - A cricketer has a certain average for 10 innings. In the eleventh inning, he scored 108 runs, thereby increasing his average by 6 runs. His new average is?

A - 52

B - 48

C - 55

D - 60

Explanation

```Let average for 10 innings be z. Then,
= 10z + 108⁄11 = 11z + 66 = 10z + 108 = z = 42.

New average = (z + 6) = 48 runs.
```

Q 10 - 3 years ago. the average age of a family of 5 members was 17 years. A baby having been born, the average age of the family is the same today. The present age of the baby is ?

A - 3

B - 4

C - 2

D - 1

```Total age of 5 members, 3 years ago = (17 x 5) years = 85 years