M4maths Previous Puzzles

25 Oct 2012 GP

A positive number is equal to the sum of all numbers after it in a geometrical progression. Common difference of GP will be

OPtion

1) 4
2) 2
3) 1/2
4) 1/3
5) 1/4
6) 2/3
7) 3/4
8) 4/5
9) 1/10
10) none of these

Solution

according to the given condition
a = ar + ar^2 + ar^3 + ar^4 + .......
so a = a[r/(1-r)]
here we use
"sum of infinite terms of GP = first term / [1 - common difference]"

Correct Option: 3 Best Solution (0)