Question

If the average of a, b, c, d is the average of b and c, then the value of a − b − c + d is ______.

Answer 1

If the average of a, b, c, d is the average of b and c, then the value of a − b − c + d is 0.

Explanation:

Equating the averages gives \[\frac{a+b+c+d}{4}=\frac{b+c}{2}\], so \[a+d=b+c\].

Therefore, \[a-b-c+d=0\].