Average Questions

Let the fixed expenditure of the hotel be Rs.x and the variable expenditure ( which is dependent on the guest ) is Rs.y , then 

          x + 10y = 600        ---------(1)

          x + 20y = 800       ----------(2)

From (1) & (2)

10y = 200 

=>  y = Rs. 20   and    x= 400

Hence the total expenditure when there are 40 guests = 400 + 40 x 20 = 1200

Therefore,  average expenditure = 1200/40 = Rs. 30

Let average for 10 innings be x. Then,

(10x + 108)/11 = x + 6 => 11x + 66 = 10x + 108  =>  x = 42.

New average = (x + 6) = 48 runs.

Let 'K' be the total number of sweets.
Given total number of students = 112
If sweets are distributed among 112 children,
Let number of sweets each student gets = 'L'

=> K/112 = L ....(1)
But on that day students absent = 32 => remaining = 112 - 32 = 80
Then, each student gets '6' sweets extra.

=> K/80 = L + 6 ....(2)
from (1) K = 112L substitute in (2), we get
112L = 80L + 480
32L = 480
L = 15

Therefore, 15 sweets were each student originally supposed to get.

Total number of students = 54 x 30
When arranged in rows of 45, number of rows formed are,
54x3045 = 36.

Let the number of students in classes A, B and C be P, Q and R respectively.
Then, total score of A = 83P, total score of B = 76Q, total score of C = 85R.
Also given that,
(83P + 76Q) / (P + Q) = 79
=>4P = 3Q.
(76Q + 85R)/(Q + R) = 81
=>4R = 5Q,
=>Q = 4P/3 and R = 5P/3
Therefore, average score of A, B, C = ( 83P + 76Q + 85R ) / (P + Q + R) = 978/12 = 81.5