- A42
- B21
- C18
- D9
Step-by-Step Solution
The middle term (arithmetic mean) is (12 + 30)/2 = 21. Then 12, 21, 30 has common difference 9.
Answer: B) 21
What is the number exactly halfway between 12 and 30, so that the three numbers form an AP?
Class 10Properties and Selection of AP TermsAlgebra — Sequences
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