The geometric sequence of the missing points is:
a is the missing points initially. Assuming 100 marks, this is 25
r = 8/10, as the missing marks reduces by 2/10 each time
[tex]u_n = 25( \frac{8}{10})^{n-1}[/tex]
Assuming the marks are out of 100, and marks are rounded to the nearest whole number, the maximum mark he can get is 98, as 2/10 of the remaining 2 marks would make it 98.4, which would round back to 98.
This series is converging, as the 8/10 gets smaller every time, so the series will eventually converge.
Hope this helps :)
