The Total solution for NCERT class 6-12
Given:
Sum of GP = 728
Where, a = 2, r = 6/2= 3, n = ?
By using the formula,
Sum of GP for n terms= a(rn – 1 )/(r – 1)
728 = 2 (3n –1)/(3-1)
728 = 2 (3n –1)/2
728 = 3n –1
729 = 3n
36 = 3n
6 = n
∴ 6 terms are requiredto make a sum equal to 728