Aptitude questions – Averages – Set 1

Q.1) Average cost of 4 ruled and 2 unruled notebooks  is Rs.38. Average cost of  7 ruled and 8 un ruled note books is Rs.52, and Average cost of 5 ruled and 6 unruled notes is Rs.45. Find the total cost of 8 ruled and 8 un ruled note books.

a) Rs.815.5

b) Rs.751.5

c) Rs.715.5

d) Rs.810.5

e) None of these

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  b

Sum of cost of 4 ruled and 2 unruled note=6×38=Rs.228

Sum of cost of 7 ruled and 8 unruled note=15×52=Rs.780

Sum of cost of 5 ruled and 6 unruled note=11×45=Rs.495

Total cost of 16 ruled and 16 unruled note=228+780+495=Rs.1503

Total cost of 8 ruled and 8 unruled notes=1503/2=Rs.751.5

Q.2) Sumith ate 70 dates in 1week. Each day he ate 2 more dates than those he ate on the earlier day. What is the average number of dates did he eat on the first, fourth and last day?

a) 13

b) 15

c) 10

d) 9

e) 11

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  c

Let number of Dates eaten on the first day x,

x+x+2+x+4+x+6+x+8+x+10+x+12=70

7x+42=70

x=28/7=4

First day=4

Fourth day=x+6=10

Last day=x+12=16

Average number of dates=30/3=10 dates

Q.3) In a class room 410 cake pieces are distributed among some girls and boys. Total number of girls is 30. Each girl gets four pieces and each boy gets five pieces. Find the average number of boys and girls in the class room?

a) 58

b) 41

c) 52

d) 44

e) None of these

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  d

Sum of cake pieces girls have=30×4=120

Number of boys=30×4+x×5=410

x=58

Average number of boys and girls in the class=(30+58)/2=44

Q.4) The total salary paid to the 25 assembly workers is Rs. 237500. The foreman’s salary is 110% of the average salary of assembly workers salary. How much salary is paid to  the Foreman?

a) Rs.13100

b) Rs.12350

c) Rs. 11900

d) Rs. 10450

e) None of these

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  d

Average salary of Assembly members=237500/25=9500

Foreman salary=9500×110/100=Rs.10450

Q.5) In an R&D department, the average monthly salary of 21 Mentors and 5 TLs in a Govt exam coaching institute was Rs.4500. When one TL’s salary was Rs.11000 was replaced with a new TL, then the average salary of the department went down to Rs.4450. what is the salary of new TL?

a) Rs.9700

b) Rs.8500

c) Rs.10500

d) Rs.9000

e) Cannot be determined

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  a

The average salary dropped by Rs.50 for 26 of them, therefore the overall salary has dropped by,

=26×50=Rs.1300

The new TL’s salary should be Rs.1300 less than the old TL’s Salary=11000-1300=Rs.9700

Q.6) Renuka went to shop and buy a chocolate pocket. Renuka thought the chocolate pocket contain more than 90 chocolates but less than 100 chocolates. Her friend Ravi thought the chocolate pocket contained more than 85 chocolates but less than 95 chocolates and another friend Ramya saw a chocolate pocket and said it  cannot be more than 93 chocolates. If all are them are correct in their estimate, what is the average of different probable number of chocolate in the pocket?

a) 93

b) 91

c) 92

d) 89

e) 90

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  c

Number of chocolate = x

According to Renuka,

90>x>100

According to Ravi,

85>x>95

According to Ramya,

x≤93

The value Satisfy all the above conditions are 91, 92 and 93.

The average is 92 chocolates in a pocket.

Required average=(91+92+93)/3=276/3=92 chocolates

Q.7) The average monthly salary of four persons are A, B, C and D is Rs. 12000. If their salary are in the ratio of A to B is 2 : 5, B to C is 5 : 1 and C to D  is 1 : 4, then what is average salary of B and D?

a) Rs.16000

b) Rs.17500

c) Rs.18000

d) Rs. 19000

e) 21000

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  c

Ratio=2 : 5: 1 : 4

Let their salary=2x+5x+x+4x=12000×4

x=48000/12=4000

B’s salary=5×4000=20000

D’s salary=4×4000=16000

Average salary of B and D=verage salary of B and D=36000/2=Rs.18000

Q.8) The sum of cube of two positive numbers is 728 and difference between their cubes is 296. Find the average of two numbers?

a) 6

b) 7

c) 14

d) 19

e) 11

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  b

According to the Question,

x^3+y^3=728—–(1)

x^3-y^3=296—–(2)

Solve the above two equation, we get

x=8 and y= 6

Average of two numbers=(8+6)/2=7

Q.9) The average weight of W, X and Y is 46 kg. If Z  replaced W. The average would be 52 kg and if Z replaced X, the average would be 56 kg, If Z  replaced Y, the average would be 48 kg. What is average weight of W, Y and Z?

a) 60 kg

b) 52 kg

c) 48 kg

d) 56 kg

e) None of these

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  d

Total weight of W, X &Y=46×3=138——(1)

Total weight of X, Y and Z=52×3=156—–(2)

Total weight of W, Y and Z=56×3=168——(3)

Total weight of W, X and Z=48×3=144——(4)

From 1, 2, 3 and 4,

W+X+Y+Z=202——— (5)

From 1& 5, Z=64 kg

From 2& 5, W=46 kg

From 3& 5, X=34 kg

From 4& 5, Y=58 kg

Average weight of W, Y and Z=168/3=56 kg

Q.10) The average weight of 19 boxes of apple is 11.5 kg, a box is added increasing the average  weight by 400 g. What is the weight of new box?

a) 20.5 kg

b) 19.5 kg

c) 21 kg

d) 18.4 kg

e) None of these

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  b

Total weight of 19 boxes=19×11.5=218.5 kg

New average=11.5+0.4=11.9 kg

Total weight of 20 boxes=20×11.9=238 kg

The weight of new box=238-218.5=19.5 kg


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