<PRE><B>Question 992312</B>
After five exams, Andrew has a mean mark of 70.
What mark must he get in the next exam to raise his average to 72?
:
let x = the mark of the 6th exam

{{{(5(70)+x)/6}}} = 72
{{{(350+x)/6}}} = 72
multiply both sides by 6
350 + x = 6(72)
subtract 350 from both sides
x = 432 - 350
x = 82 is the grade must get to raise his average to 72
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