Average questions and answers

AVERAGE QUESTIONS AND ANSWERS

1) 20 pens and 55 pencils were purchased for Rs.600.If the average price of a pencil was Rs.2 , find the average price of a pen ?

Explanation: Since average price of a pencil = Rs. 2 Therefore Price of 55 pencils = Rs.110 , Price of 20 pens =600-110 = 490 average price of a pen = 490/20 =24.5 Ans: 24.5

2) A man walks 2500 metres in 40 minutes , 1000 metres in 30 minutes and 500 metres in 10 minutes.

Then what is the average speed for whole walking distance ?

Explanation: Average marks = (2500+1000+500) / (40+30+10) = 4000 / 80 = 50 Ans : 50

3) Anil travels to a place 200 km away at an average speed of 70 km/hr and returns at 32 km/hr. Find the average speed for whole journey in km/hr ?

Explanation: Average speed = 2xy/ x+y .

Average speed of given problem = (2*70*32) / 70+32 (140 *32) /102 = 4480/102 = 43.92 Average speed of given problem =43.92.

Ans: 43.92.

4) Find the average of cubes of consecutive 10 natural numbers ?

Explanation: 10(10+1)² / 4 = (110)²/4 = 12100 /4 = 3025 Average of cubes of consecutive n natural numbers= n(n+1)² / 4.

Ans: 3025

5) Find the arithmetic mean of 3 , 5 , 7 , 8 , 13 , 17 ,22 and x. Mean is 10 ,what should be the number in place of x ?

Explanation: Mean or average = (3+5+7+8+13+17+22+x) / 8 =10 ----> (75 +x) /8 =10 -------> x = 80 -75 = 5.

Ans: 5

6) Find the average of all the numbers between 5 to 25 , which are divisible by 3 ?

Explanation: Average = ( 6+9+12+15+18+21+24) / 7 = 105 / 7 =15.

Ans: 15

7) Find the average of consecutive 25 natural numbers ?

Explanation : (25+1) / 2 = 26/2 = 13 Average of consecutive n natural numbers = (n+1)/2 Ans: 13

8) Find the average of consecutive even numbers to 80 ?

Explanation : Average = ((N/2)+1) =(80/2)+1 = 40+1 = 41.

Ans : 41

9) Find the average of consecutive natural numbers from 20 to 80 ?

Explanation : Average = (1st number + last number) / 2.

So Average of given numbers = (20+80) / 2 =100/2 =50.

Ans : 50

10) Find the Average of first 50 naturals numbers ?

Explanation : Sum of first n natural numbers = n(n+1)/2.

So (50*51)/2 =1275 , There fore Required average = 1275/50 = 25.5 Ans: 25.5

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