WAEC - Further Mathematics (2006 - No. 34)
The mean and median of integers x, y, z and t are 5 and z respectively. If x < y < z < t and y = 4, find (x + t).
12
11
10
8
Explanation
\(Mean : \frac{x + 4 + z + t}{4} = 5 \implies x + 4 + z + t = 20\)
\(\implies x + z + t = 16 ... (1)\)
\(Median : \frac{4 + z}{2} = z \implies 4 + z = 2z\)
\(4 = z\)
From 1,
\(\implies x + 4 + t = 16 \)
\(x + t = 12\)
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