The average of x occurring 5 times and y occurring 7 times is 37. Also, the average of x occurring 7 times and y occurring 5 times is 35. The value of y is:
Answer
Correct Answer : b ) 42
Explanation :It is given that:
Average of 5x and 7y = 37
Average of 7x and 5y = 35
We can write that,
(5x + 7y)/ 12 = 37
5x + 7y = 444 ....(1)
(7x + 5y)/ 12 = 35
7x + 5y = 420 ....(2)
Multiply eq. 2 by 5 and subtract from the multiplication of eq. 1 by 7
35x + 49y = 3108
-35x - 25y = -2100
24y = 1008
y = 42.
Hence, (b) is the correct answer.
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