Check out some similar questions!

ferna007 · Jan 25, 2010, 02:48 AM

1.three numbers are in AP and their sum is 15. If 8,6,4 are added to them respectively,they form a GP.The numbers are.
Please tell me the solution and method of solving this type of questions using this formula for Ap:(a-d),a, (a+d) and for GP:a/r,a,ar
The option for the above question is :A)2,6,7 B)4,6,5 C) 3,5,7

The above is question of AP and GP.

Curlyben · Jan 25, 2010, 03:04 AM

Thank you for taking the time to copy your homework to AMHD.
Please refer to this announcement: https://www.askmehelpdesk.com/financ...-b-u-font.html

Unknown008 · Jan 25, 2010, 08:00 AM

Formula for the nth term of an AP:

$T_n = a + (n-1)d$

The sum of n terms in an AP is:
$S_n = \frac12 (a+l) = \frac12 (2a + (n-1)d)$

Those fot a GP;
$T_n = ar^{(n-1)}$

$S_n = \frac{a(1-r^n)}{1-r} \ for\ r\cancel{=} 1$

$S_n = \frac{a}{1-r} \ for\ |r|<1$

Post what you did.