<PRE><B>Question 319332</B>
On an exam with q questions, Marie correctly answered 15 of the first 20
 but just 1/3 of the rest. 
If her total score was 50%, what was q?
:
.50q = 15 + {{{1/3}}}(q-20)
Multiply equation by 3, to get rid of the fraction, results:
3(.5q) = 3(15) + q - 20
:
1.5q - q = 45 - 20
:
.5q = 25
Multiply both sides by 2
q = 50
:
:
Check solution
15 + 1/3(50 - 20) =
15 + 10 = 25 which is 50% of 50</PRE>