Question 4636
on the 4 test so far, he has averaged 4*74 --> 296 marks out of 400.


We need to find the score on the final exam (out of 100) to bring his average up to 80% or better. And this final exam is counted double:


so, {{{((296+x+x)/600)*100 = 80}}}

{{{((296+2x)/6) = 80}}}
{{{(296+2x) = 480}}}
2x = 480-296
2x = 184
so x = 92


jon