13. A counterexample
2 answers:
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Some parts are missing in the queston. Find attached the picture with the complete question
Answer:
Explanation:
Let's put the information in a table step-by step.
(number of remaining students)
Juniors Seniors
Condition
- Initially J S
- 15 seniors left S - 15
- Twice juniors as seniors 2(S - 15)
- 3/4 of the juniors left 1/4×2(S - 15)
- 1/3 of seniors left 2/3×(S - 15)
At the end, there were 8 more seniors than juniors:
- 2/3×(S - 15) - 1/4×2(S - 15) = 8
Now you have obtained one equation, which you can solve to find S, the number of senior students, and then the number of junior students.
Solve the equation:
- Mutilply all by 12:
- Distribution property:
- Addtion property of equalities:
- Add like terms:
- Division property of equalities:
That is the number of senior students that came out to the information meeting, but the number of students remaining to perform in the school musical is (from the table above):
Just substitute S with 153 fo find the number of students that remained to perfom in the musical:
