Question

If a geometric sequence starts with a first term of 2 and grows exponentially by a factor of 3,
what is the sum of the 4th and 5th terms?
A) 215
B) 220
C) 216
D) 218

Answer 1

Answer:

216 option (C)

refer the above picture.

Answer 2

Step-by-step explanation:

• Now according to the question we have
• With first term of 2 the geometric sequence starts
•                       So a = 2
•                  Also r = 3
• n is the number of terms
• So we have
•                     ar^n – 1
•           Now we have  n = 1,2,3,4,5 we get
•            Considering n = 1 we get  2(3)^1 – 1 = 2(3)^0 = 2
•            Considering n = 2 we get  2(3)^2 – 1 = 2(3)^1 = 6
•           Considering n = 3 we get  2(3)^3 – 1 = 2(3)^2 = 18
•          Considering n = 4 we get  2(3)^4 – 1 = 2(3)^3 = 27 x 2 = 54
•             Considering n = 5 we get  2(3)^5 – 1 = 2(3)^4 = 81 x 2 = 162
• Now the question is to find the sum of 4th and 5th term  So we get 54 + 162 = 216

Reference link will be

https://brainly.in/question/4153293