2017 · Q56
Let a, b, c, d, e, f, g be consecutive even numbers and j, k, I, m, n be consecutive odd numbers. What is the average of all the numbers ?
Elementary MathematicsStatistics
- A(3(a+n))/2
- B(5l+7d)/4
- C(a+b+m+n)/4
- DNone of the above
Explanation
The mean of the 7 consecutive evens is their middle term d, and of the 5 consecutive odds is their middle term l, so the overall mean is (7d + 5l)/12. None of options A–C equals this, so 'None of the above': option D.