If the G.Ps 5 , 10, 20, and 1280, 640, 320 have their nth terms equal, find the value of `ndot`

Explanation

To solve the problem, we need to find the value of \( n \) such that the \( n \)-th terms of the two given geometric progressions (G.P.s) are equal.

### Step-by-Step Solution:

1. **Identify the first G.P.**:
The first G.P. is given as \( 5, 10, 20 \).
- The first term \( a = 5 \).
- The common ratio \( r = \frac{10}{5} = 2 \).
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