Reciprocal APMediumQuestion 210010
Question
If a, b, c are in AP, then 1/bc, 1/ca, 1/ab are in:
- AAPCorrect
- BGP
- CHP
- DNone
Correct answer
AP
Explanation
If a, b, c are in AP (2b = a+c), then dividing 1/(abc) from each side: (a/abc), (b/abc), (c/abc) etc. 1/bc, 1/ca, 1/ab are in AP since 2/ca = 1/bc + 1/ab → 2 = c/b + a/b → 2b = a+c ✓.