Average Practice Test 1

Let the weight of the first member = 5
Weight of the second member = x
Average weight the first and the second member = 6
$\frac{5+\mathit{x}}{2}=6$
$\mathit{x}=12-5=7$
Weight of the second member = 7
Let the weight of the third member = x
Now Average of the first, second and third member is 7
$\frac{5+7+\mathit{x}}{3}=7$
$\mathit{x}=9$
Similarly, we can derive the weight of the fourth and the fifth number, i.e., 11 and 13 respectively.
Difference between the weight of the last player and the first player = 13 - 5 = 8 kg