Question 370527
Let x = # of multiple choice questions answered correctly.



So because "A student scored 78 on a test" and "the student had one fill in wrong", this must mean that {{{3*7+3x=78}}}



Note: because the student missed one fill in question, this means that s/he got 3*7 points so far.



{{{3*7+3x=78}}} Start with the given equation.



{{{21+3x=78}}} Multiply



{{{3x=78-21}}} Subtract {{{21}}} from both sides.



{{{3x=57}}} Combine like terms on the right side.



{{{x=(57)/(3)}}} Divide both sides by {{{3}}} to isolate {{{x}}}.



{{{x=19}}} Reduce.



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Answer:


So the solution is {{{x=19}}}



This means that the student answered 19 multiple choice questions correctly. 



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