# Aptitude questions – Averages – Set 2

Q.1) In a examination the average marks obtained by a student is 73 per paper. If he had obtained 31 marks more in economy paper & 17 more marks in Computer paper, then his average per paper is increased by 4 marks. Then how many papers were there in examination?

a) 12

b) 14

c) 15

d) 11

e) None of these

a

Let the number of paper be X.

Then total marks earned him = 73X

From question,

73X + 31 + 17 = 77X

4X = 48   =>   X = 12 = number of subjects

Q.2) The average rainfall for the first five days out of seven days was recorded to be 5.5 cm. The rainfall on last two days is 5.4 cm and x cm. The average of seven days was 5.6 cm. What is the value come in the place of x?

a) 6.66 cm

b) 9.6 cm

c) 6.3 cm

d) 5.5cm

e) None of these

c

According to the question,

(5×5.5+5.4+x)/7=5.6

x=6.3 cm

Q.3) In a famous hotel the rooms were numbered from 101 to 140, each room gives an earning of Rs.3500 for the first fifteen days of a month and for the latter half, Rs.4000 per room. Find the average income per room per day over the month of 31 days? (Approximately)

a) Rs.3897

b) Rs.3758

c) Rs.3900

d) Rs.3290

e) None of these

b

Total number of rooms =40

Earning in first 15 days per room= 15×3500 = Rs. 52500

Earning in second 16 days = 16×4000 = Rs. 64000

Average income per room per day over the month of 31 days,

= ((52500+64000))/31  =  Rs.3758

Q.4) Of the three numbers, second is twice the third and is thrice the first. If average of the three numbers is 55, then largest number is

a) 95

b) 76

c) 90

d) 93

e) 88

c

Let third number is be x,

Then second number=2x

First number=2x/3

x+2x+2x/3=(55×3)

11x/3=165

x=45

Largest number-2x

=2×45=90

Q.5) In factory machines are  running the same constant rate. 5 machines can produce a total of 250 materials per hour. At this rate, how many materials could 8 such machines produce in 3 hour?

a) 1387

b) 1200

c) 1367

d) 1208

e) None of these

b

5 machines can produce= 250 materials

1 machile can produce=250/5=50 Materials/ hr

8 machines can produce the material=50×8=400

8 machines can produce  materials=400×3=1200

Q.6) The average height of 11 persons is 144 cm, the average height of first 5 persons is 156 cm, and the average height of last 4 persons is 139 cm. Find the  sum of the heights of 6th and 7th persons

a) 310 cm

b) 248 cm

c) 298 cm

d) 342 cm

e) None of these

b

Sum of height of 11 persons=11×144=1584cm

Sum of height of first five person=5×156=780cm

Sum of height of last 4 persons=4×139=556cm

sum of 6th and 7 th persons height=1584-(780+556)=248

Q.7) The average temperature of a week is C. Every day the temperature decreases by  from the previous day. Find the total temperature of Wednesday, Friday & Sunday if first day of the week is Monday?

a) 750C

b) 650C

c) 720C

d) 690C

e) None of these

a

Let the temperature of first day be Xo C.

Then, total temperature of the week = X+X-2+X-4+….+X-12 = 27 × 7

7X – 42 = 189 => X = 33 = Temperature on Monday

Total temperature of Wednesday, Friday & Sunday = 29 + 25 + 21 =750C

Q.8) A car company produced an average of 1500 cars per year for the first 2 years. How much cars it must produce on an average per year over the next 3 years to average 1575 cars per year over the 5 year?

a) 1755

b) 1625

c) Cannot be determined

d) 1865

e) None of these

b

Let average production of a company in 3 years be x cars,

1575= (2×1500+3×x)/5

1575×5=3000+3x

x=4875/3=1625

Q.9) The average age of X, Y, and Z is 2 years less than X age. Y’s age is twice as the Z ‘s age, If Y age was 36 years. Then X age is,

a) 24 yrs

b) 28 yrs

c) 31 yrs

d) 18 yrs

e) 30 yrs

e

Average age of X, Y,Z=(X+Y+Z)/3=(x-2)

Y’s age=2Z

Y=36 yrs

Z^’ s age=36/2=18 yrs

apply the value of Y, Z in above equation,

=>(x+36+18)/3=(x-2)

x=30 yrs

Q.10) Second number is equal to the twenty percent of third number. Third number is equal to the two-fifth of fourth number. If the value of fourth number is 6800, the first number is equal to the 25% of second number. Find the average value of the four numbers,

a) 2550

b) 2680

c) 3890

d) 3280

e) 4109