Problema Solution
find four consecutive terms in AP such that sum of all is 66 and product of the extremes to product of means is 14:15.
Answer provided by our tutors
Let the terms are (x-3d),(x-d),(x+d),(x+3d)
Sum =4x = 66
=> x= 66/4=16.5
Also ((x-3d)(x+3d))/((x-d)(x+d))= 14/15
=> (x2- 9d2 )/(x2 - d2)= 14/15
=> 15x2- 135d2 = 14x2 - 14d2
=> x2 =121d2
=> x= 11d
=> d =x/11 = 16.5/11 = 1.5
The terms are :- (16.5-3*1.5),(16.5-1.5),(16.5+1.5),(16.5+3*1.5)
=> 12,15,18,21