1.Find the average of the following set of scores
253, 124, 255, 534, 836, 375, 101, 443,760
EXPLANATION
Required average = sum of all scores/number of scores
=( 253 + 124 + 255 + 534 +836 + 375 + 181 + 443 + 760) /9
= 3681/9
= 409
2. What will be the average of even numbers between 11 to 63?
EXPLANATION
Even numbers between 11 to 63 = 12, 14, 16,.........,62
Clearly this is a series of consecutive even numbers
According to the formula
Average of consecutive even numbers
= (First number + Last number) / 2
= ( 12 + 62) / 2
= 37
Fast Track Techniques to solve the QUESTIONS of AVERAGE
3. A businessman purchased 30 TV sets in 300000. If the average cost of 15 TV sets is 9000, then find out the average cost of remaining TV sets.
EXPLANATION
Here m = 30, n = 15
Average cost of 30 TV = 300000/30 = 10000
Therefore a = 10000, b = 9000
Average cost of remaining (30- 15) tv
= ( 30 × 10000 - 15 × 9000) / (30 - 15)
= 165000/15
= 11000
4. The average of four consecutive numbers A, B, C and D is 49.5. What is the product of B and D.
EXPLANATION
Let the numbers of A, B, C and D are x, x + 1, x + 2 and x + 3 respectively.
According to the question,
[ x +( x+1)+(x+2)+(x+3)] / 4 = 49.5
4x + 6 = 49.5× 4
4x = 198 - 6
x = 192 / 4
= 48
The required product = B × D
= ( 48 + 1) ×( 48 + 3)
= 49 × 51
= 2499
5. A cricketer has a mean score of 60 runs in 10 innings. Find out how many runs are to be scored in the eleventh innings to raise the mean score to 62?
EXPLANATION
Here, n = 10. a = 60, b = 62
Number of runs scored in 11th inning = n (b - a) + b
= 10 (62 - 60) + 62
= 20 + 62 = 82
253, 124, 255, 534, 836, 375, 101, 443,760
EXPLANATION
Required average = sum of all scores/number of scores
=( 253 + 124 + 255 + 534 +836 + 375 + 181 + 443 + 760) /9
= 3681/9
= 409
2. What will be the average of even numbers between 11 to 63?
EXPLANATION
Even numbers between 11 to 63 = 12, 14, 16,.........,62
Clearly this is a series of consecutive even numbers
According to the formula
Average of consecutive even numbers
= (First number + Last number) / 2
= ( 12 + 62) / 2
= 37
Fast Track Techniques to solve the QUESTIONS of AVERAGE
3. A businessman purchased 30 TV sets in 300000. If the average cost of 15 TV sets is 9000, then find out the average cost of remaining TV sets.
EXPLANATION
Here m = 30, n = 15
Average cost of 30 TV = 300000/30 = 10000
Therefore a = 10000, b = 9000
Average cost of remaining (30- 15) tv
= ( 30 × 10000 - 15 × 9000) / (30 - 15)
= 165000/15
= 11000
4. The average of four consecutive numbers A, B, C and D is 49.5. What is the product of B and D.
EXPLANATION
Let the numbers of A, B, C and D are x, x + 1, x + 2 and x + 3 respectively.
According to the question,
[ x +( x+1)+(x+2)+(x+3)] / 4 = 49.5
4x + 6 = 49.5× 4
4x = 198 - 6
x = 192 / 4
= 48
The required product = B × D
= ( 48 + 1) ×( 48 + 3)
= 49 × 51
= 2499
5. A cricketer has a mean score of 60 runs in 10 innings. Find out how many runs are to be scored in the eleventh innings to raise the mean score to 62?
EXPLANATION
Here, n = 10. a = 60, b = 62
Number of runs scored in 11th inning = n (b - a) + b
= 10 (62 - 60) + 62
= 20 + 62 = 82
