On a certain multiple-choice test, 9 points are awarded for each correct answer, and 7 points are deducted for each incorrect or unanswered question. Sally received a total score of 0 points on the test. If the test has fewer than 30 questions, how many questions are on the test?

Question

danjs · Answer

9*(#correct) - 7*(#wrong) = 0                 --given

danjs · Answer

there are two variables there and only one equation, need one more to be able to solve

anonymous · Answer

Cannot be determined
16
19
21
24

danjs · Answer

If the test has fewer than 30 questions...  that is the second given thing

danjs · Answer

Total questions = #correct + #wrong

danjs · Answer

which is less than 30

campbell_st · Answer

just write it as a ratio 

9 correct = 7wrong

so the ratio is 9:7 

16 parts

so 7 correct and 9 wrong

danjs · Answer

that works

anonymous · Answer

can we also use 9x7 and 7x9 ?

danjs · Answer

what cambell did was take the first equation that was given..
9*(#correct) - 7*(#wrong) = 0 

and solve it as a ratio of correct/wrong

danjs · Answer

and the total correct and wrong has to be less than 30

anonymous · Answer

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