defence exam Coast Guard Navik GD (General Duty) 02/2025 Mock Test Series Mathematics Sequences and Series Geometric Progressions
Let a, ar, ar2, ........ be an infinite G.P. If \(\displaystyle\sum_{n=0}^{\infty}\rm ar^n = 57\) and \(\displaystyle\sum_{n=0}^{\infty}\rm a^3r^{3n} = 9747\), then a + 18r is equal to :
1
27
2
46
3
38
4
31