CA Foundation · Quantitative Aptitude · Sequence and Series
Two geometric means are inserted between 5 and 135. What is the sum of these two geometric means?
The sum of the two geometric means is 60. With first term 5 and fourth term 135, r cubed equals 27, so r is 3. The inserted terms are 15 and 45, which add up to 60.
- A60Correct
- B45
- C30
- D75
Explanation
We have 4 terms in GP with a = 5 and fourth term 135, so r³ = 135/5 = 27 and r = 3. The means are 15 and 45, and their sum is 60. The value 75 would come from using the wrong number of ratios.
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