Question

If three geometric means are inserted between 10 and 160, then find the 3^rd geometric means.
1. 40
2. 80
3. 120
4. 100

Answer 1

Correct Answer - Option 2 : 80

Given:

Three geometric means are inserted between 10 and 160.

Formula Used:

rⁿ = (b/a)

y^th term = a × r^y

Where a is First term

b is Last term

r is Common ratio

n is Number of terms

Calculation:

rⁿ = (b/a)

⇒ r⁴ = (160/10)

⇒ r⁴ = 16

⇒ r = 2

3^nd term = a × r³

⇒ 10 × 2³

⇒ 10 × 8

⇒ 80

∴ The 3^rd geometric means is 80.