Question

Evaluate S5 for 600 + 300 + 150 + … What's the answer?

A.) 1,162.5
B.) 581.25
C.) 37.5
D.) 18,600

Answer 1

A

Explanation:

:)

Answer 2

The answer is 1,162.5 ⇒ answer A

Explanation:

The series is 600 + 300 + 150 + ......

∵ 300 ÷ 600 = 0.5

∵ 150 ÷ 300 = 0.5

- Each number multiplied by 0.5 to get the next number, that means

we have constant ratio in this series between each tow consecutive

terms then the series is geometric

- The rule of the sum of the geometric series is:

`S_(n)=(a(1-r^(n)))/(1-r)`, where a is the first term in the series,

r is the constant ratio between each two consecutive terms and n is

the position of the term in the series

- We need to find
`S_(5)`

∵ a = 600 , r = 0.5 and n = 5

Substitute all of these values in the rule above to find
`S_(5)`

∴
`S_(5)=(600(1-0.5^(5)))/(1-0.5)=1162.5`

The answer is 1,162.5