\sum _ { n = 1 } ^ { \infty } ( \frac { 1 } { 5 ^ { n } } + \frac { 2 ^ { n } + 3 ^ { n - 1 } } { 5 ^ { n } } )∑ n=1
∞
​
(
5
n

1
​
+
5
n

2
n
+3
n−1

​
)​

Plz re-post your question

11.82%

Step-by-step explanation:

We are given that

Cost to store A=4162

Cost to store=$155

Cost to store C=$160

Markup for store A=40%

Markup for store B=30%

Markup for store C=25%

Markup price=Cost price\times (100+markup)

Markup price for store A=$226.80

Markup price for store B==$201.50

Markup price for store C=$200

So, the best deal is store C.

If we purchased from  store A then the price should be less than store C.

It means the price of store A should be less than $200 that is $199.99.

Discount=226.80-199.99=$26.81

Discount %=

Hence, the store A  must offer discount 11.82% to buy the system there.