Sun, 05/04/2015 - 09:24

#1
Challenging Math, anyone?

The sum of the first 100 terms of an arthmetic progresion is 15050.The first,third and eleventh terms of this progression are 3 consecutive terms of a geometric progression.Find the first term, and common difference of the arithmetic progression.

yh

sum of n terms of an AP=n/2[2a+(n-1)d]

1st a

3rd a+2d

11th a+10d

a+2d/a=a+10d/a+2d

6a-4d=0......... eqt 1

2a+99d=1505......eqt 2

a simulteneuos equation

solve.

try that.

yessss me , i need help!!