Question

There are three numbers. If the average of any two of them is added to the third number, the sums obtained are 177, 163 and 138. Whatis the average of the largest and the smallest of the given numbers?

A 67 Correct Answer Incorrect Answer
B 81 Correct Answer Incorrect Answer
C 79 Correct Answer Incorrect Answer
D 76 Correct Answer Incorrect Answer

Solution

Let the three numbers be x, y, z. X+y / 2 + z = 177 x + y + 2z = 354 …(1) Y + z / 2 + X = 163 2x + y + z = 326 …(2) x + z / 2 + y = 138 x + 2y + z = 276 …(3) Adding eq(1),(2),(3) and dividing it by 4, we get x + y + z = 239 ,,,(4) sub (1) - (4), z = 115 sub (2) - (4), x = 87 sub (3) - (4), y = 37 The average of largest and smallest = 115+37/2 = 76

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