Question 316966
dont u mean 3 tests since theres clearly no indication to find the 4th one and with a 2nd variable it would make for an incredible guess and check question with lots of possibilities. so im going to assume u meant 3 tests
{{{(60+80+x)/3=72}}}
{{{(140+x)/3=72}}}
{{{(140+x)=216}}}
{{{x=76}}}
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just to show u what the problem would be with 2 unknowns:
{{{(60+80+x+y)/4=72}}}
{{{(140+x+y)=288}}}
{{{(x+y)=148}}}
as u can se there are many possibilities for what x or y could be, which would make a question like this unanswerable.
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good luck