If the ratio of the sum to n terms of two A.P.'s is (5n+3):(3n+4), then the ratio of their 4th terms is
(3)
Given n2[2a1+(n-1)d1]n2[2a2+(n-1)d2]=5n+33n+4
For n=7, a1+3d1a2+3d2=3825