11 is related to 79 by a certain rule, and 9 is related to 63 by the same…
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11 is related to 79 by a certain rule, and 9 is related to 63 by the same rule. Using that rule, which value is related to 15?
Note: Perform operations on each whole number as a unit. Do not split a number into its digits. For example, you may add to, subtract from, or multiply 13 as a whole, but you may not split it into 1 and 3.
Answer: C. 111 — ConceptIn a number analogy, apply one identical operation to each input. A valid rule must reproduce every given input-output pair before it is used on the…
- A.
114
- B.
119
- C.
111
- D.
105
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Correct answer: C
Concept
In a number analogy, apply one identical operation to each input. A valid rule must reproduce every given input-output pair before it is used on the new input.
Application
Test the rule output = input × 8 − 9 on 11: 11 × 8 − 9 = 88 − 9 = 79.
Apply the same rule to 9: 9 × 8 − 9 = 72 − 9 = 63, so it fits both given pairs.
Apply it to 15: 15 × 8 − 9 = 120 − 9 = 111.
Cross-check
Working backward from 111 gives (111 + 9) ÷ 8 = 120 ÷ 8 = 15, confirming the relation. Therefore, 15 is related to 111.