when each of the 20 numbers is multiplied by 24, the average will also be raised to 24 times

so the new avg :- 24 x 14 = 336

If x be the total marks then,

x * (64/100) = 2240 – 128 = 2112

Or, x = 2112 * (100/64) = 3300

Marks obtained by Meena = 2240 – 907 = 1333

So, the percentage of marks obtained by Meena = (1333/3300) * 100 = 40.39% ≈ 40%

Let the first number be 3x. Second number is 6x. Third number is 2x.
So average = (2x + 3x + 6x)/3 = 11x/3
But 11x/3 = 44
So, x = 12
6x = 72

Let his monthly salary be x rupees.
So, 5 (x – 1200) + 7 (x-1300) = 2900
12x – 6000 – 9100 = 2900
So, x = 18000/12 = 1500

Total age of 4 members, 10 years ago = (24 x 4) years = 96 years.

Total age of 4 members now = [96 + (10 x 4)] years = 136 years.

Total age of 6 members now = (24 x 6) years = 144 years.

Sum of the ages of 2 children = (144 – 136) years = 8 years.

Let the age of the younger child be x years.

Then, age of the elder child = (x+2) years.

So, x+(x+2) =8 <=> x=3

Age of younger child  =  3 years.

Average speed =[2xy /(x+y)]km/hr.
=[(2*84*56) /(84+56)] km/hr.
=[(2*84*56)/140] km/hr.
= 67.2km/hr.

Sum of the marks for the 12 students = 12 * 36 = 432. The marks of each student are doubled, the sum also will be doubled.
The new sum = 432 * 2 = 864. So, the new average = 864/12 = 72.

Excluded number = (27 x 5)  –  (25 x 4) = 135 – 100 = 35.

 A+B+C = 12000*3
B+C+D = 15000*3
→ D-A = 3000*3 = 9000
Also, D = 2A
Then, D = 18000 and A = 9000
Therefore,
Average salary of B and C,
= (45000-18000)/2 = 13,500.

1st Method:
Average of 1st n natural number is given by = ([n*(n+1)]/2)/n
Average of 1st 97 natural number is given by = {([97*(97+1)]/2)/97} = 49

2nd Method:
These numbers are in AP series, so average,
= (sum of corresponding term)/2
= (1+97)/2 = 49
Or, (2+96)/2 = 49
Or, (3+95)/2 = 49 And so on.

Total pice of the two books = Rs. [(12 x 10) – (11.75 x 8)]

= Rs. (120 – 94) = Rs. 26.

let the price of one book be Rs. x

Then, the price of other book = Rs. (x + 60% of x) = Rs.(x+(3/5)x) = Rs. (8/5)x

So,  x+(8/5)x =26 <=> x =10

The prices of the two books are Rs. 10 and Rs. 16

Let Arun’s weight by X kg.

According to Arun, 65 < X < 72

According to Arun’s brother, 60 < X < 70.

According to Arun’s mother, X <= 68

The values satisfying all the above conditions are 66, 67 and 68.

Total weight of boys in the class = 25 *48 = 1200 kgs

Total weight of all students in the class = 45 * 40 = 1800 kgs

Total weight of the girls in the class = 1800 – 1200 = 600 kgs

Average weight of girls =  = 40 kgs

Average after 11 innings should be 36

So, Required score = (11 * 36) – (10 * 32)
= 396 – 320 = 76

Average of the first ‘n’ natural numbers = (n + 1)/2
We get (20 + 1)/2 = 10.5