3
Answer: DSet 3: Linear Equations (Advanced)
Explanation
A number is increased by 20%, then decreased by 15%. The result is 51. What was the original number?
What was the original number?
A.
52
B.
45
C.
48
D.✓ Correct
50
Detailed Explanation
Choice D is correct. Let n = original. After +20%: 1.2 n. After -15%: 0.85(1.2 n) = 1.02 n = 51. So n = 50.
Key Steps:
•
The correct answer is 50
Why others are wrong:
A: Choice A is incorrect and may result from a calculation error.
B: Choice B is incorrect and may result from a calculation error.
C: Choice C is incorrect and may result from a calculation error.
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