Examples(Set 1) - Average

1. sampreet's special biryani has a sale of ₹ 310 , ₹ 280 , ₹ 320 , ₹ 340 and ₹ 230 for 5 consecutive months. How much sale must he have in the sixth month so that he gets an average sale of ₹ 300 ?
A. ₹370
B. ₹420
C. ₹355
D. ₹400

Answer: Option D

Explanation:
Let the sale in the sixth month be= x
the average sale of all six months = ₹300
(310+200+320+340+230+x)/6 = 300
x=400






2. aashish calculates the average of 20 numbers as zero. How many of them may be greater than zero, at the most?
A. 1
B. 20
C. 0
D. 19

Answer: Option D

Explanation:
Average of 20 numbers = 0
⇒ sum of 20 numbers = 0 × 20 = 0
Hence at the most, there can be 19 positive numbers. For example, if the sum of these 19 positive numbers is x , 20 th number can be − x
such that net sum will be zero.






3. The captain Aditya of a football team of 11 members is 26 years old and the striker Vrushabh is 3 years older. If the ages of these two are excluded, the average age of the remaining players is one year less than the average age of the whole team. Find out the average age of the team.
A. 21 years
B. 23 years
C. 24 years
D. 20 years

Answer: Option B

Explanation:
let the average age of the 9 players excluding the Captain Aditya and Vrushabh be =y
(sum of the ages of 9 players)/9=y
sum of ages of 9 players =9y

let the average age of the whole team be=x
(sum of the ages of 11 players)/11=x
sum of ages of 11 players =11x

given: x-1=y (If the ages of these two are excluded, the average age of the remaining players is one year less than the average age of the whole team)

sum of 11 players =sum of 9 players + age of Aditya + age of Vrushabh
11x=9y+26+29
11x=9(x-1)+55
11x=9x-9+55
x=23






4.The average monthly income of Aarya and Raghav is ₹ 5050. The average monthly income of Raghav and Chetan is ₹ 6250 and the average monthly income of Aarya and Chetan is ₹ 5200. What is the monthly income of Aarya?
A. ₹ 2000
B. ₹ 5000
C. ₹ 4000
D. ₹ 3000

Answer: Option C

Explanation:
Let monthly income of Aarya = a
monthly income of Raghav = b
monthly income of Chetan = c
a + b = 2 × 5050
b + c = 2 × 6250
a + c = 2 × 5200
solving the above three equations
a=4000
That is, monthly income of Aarya is ₹ 4000






5. In the first 5 overs of a cricket game, the run rate of RCB team was only 4 What should be the run rate in the remaining 15 overs to reach the target of 200 runs?
A. 12
B. 11.5
C. 13.2
D. 11

Answer: Option A

Explanation:
let the runs scored in the first 5 overs be=x
let the runs scored in the last 15 overs be =y
x+y =200

run rate in first 5 overs=4
x/5=4
x=20

x+y=200
y=180

run rate in last 15 overs=y/15
=180/5
=12






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