Question
There are three classes P, Q and R. The average marks of
class P is 75. The average marks of class Q is 80. The average marks of class R is 85. The average marks of class P and Q is 77, the average marks of class Q and R is83. Find the approximate average marks of three classes.Solution
By allegation method: 
So the ratio of students in class P to Q comes out to 3 : 2 & the ratio of students in class Q to Ris 2 : 3. Ratio of students in P, Q and R = 3 :2 : 3 So, average of all the classes = `(75xx3 + 80 xx2 + 85xx3)/(3+2+3)` = `(225+160+255)/8` = 80
More Average Questions
Find the simplified value of the given expression:
{(1 x 2) + (3 + 4) - (5 x 6) + (7 + 8) - (9 x 10)}
40 × 5 + 27) × 9 = ?
4368 + 2158 – 596 - ? = 3421 + 1262
115% of 40 + 3 × 4 = ? × 11 – 8
2850 ÷ 2.5 - ? × 42 = 300
What will come in the place of question mark (?) in the given expression?
(5/8) × 1600 + (2400 ÷ 25) = ?Â
236.23-653.23+696.23=?
15848 ÷ 4 – 793 × 6 + 3628 = 3 × ?
(1/3) + (2/5) + (3/4) + (11/10) = 3 – (?/12)
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