Divide 56 in four parts in A.P. such that the ratio of the product of their extremes (1st and 4th) to theproduct of middle (2nd and 3rd) is 5:6. any other methods to solve itplease help me fast its very important please About the author Anna
Answer: Let 4 parts in AP be a, a +d, a+2d, a+3d It is given a+(a+d)+(a+2d)+(a+3d)=56 4a+6d=56 2a+3d=28 {a×(a+3d)}/{(a+d)(a+2d)} Cross multiply then simplify a^2+3ad-10d^2=0 Factorise by mid term splitting (a+5d)(a-2d)=0 a=-5d a=2d put this value of a in equation 2a+3d=28 -10d+3d=28 -7d=28 d=-4 a=20 So AP 20, 16,12,8 You will get another set when you take another value of d Reply
Answer:
Let 4 parts in AP be a, a +d, a+2d, a+3d
It is given
a+(a+d)+(a+2d)+(a+3d)=56
4a+6d=56
2a+3d=28
{a×(a+3d)}/{(a+d)(a+2d)}
Cross multiply then simplify
a^2+3ad-10d^2=0
Factorise by mid term splitting
(a+5d)(a-2d)=0
a=-5d
a=2d
put this value of a in equation
2a+3d=28
-10d+3d=28
-7d=28
d=-4
a=20
So AP 20, 16,12,8
You will get another set when you take another value of d