Answer:
Step-by-step explanation:
a1 = 3(1) - 7 = - 4
a2 = 3(2) - 7 = -1
d = a2 - a1
d = -1 - (-4)
d = -1 + 4
d = 3
a60 = 3(60) - 7
a60 = 180 - 7
a60 = 173
n = 60
Sum = (a1 + a60) * n / 2
Sum = (-4 + 173) * 60/2
Sum = (169)*30
Sum = 5070
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Just to check, we'll use the second summation formula
d = 3
n = 60
a1 = -4
Sum = (2*a1 + (n - 1)*d )*n / 2
Sum = (2*(-4) + (60 -1)*3)* 60/2
Sum = (-8 + 59*3) * 30
Sum = (177 - 8)*30
Sum = 169 * 30
Sum = 5070
Same answer.
The price of this more expensive book was $90.00 ($150 - $60) based on the date acquired from the question above. This problem can be solved using a simple algebra equation which consisted of one variable. The equation is stated as $150 = x + 1.5x (x = $150/2.5 = $60) where x is the price of the cheaper book and 1.5x is the price of the more expensive books because it has 50% higher price than the cheaper book<span>.</span>
There is a 96% customer retention rate for the third quarter.
Given
Jenny owns a salon.
She had 150 customers at the end of the third quarter, 151 customers at the beginning of the third quarter, and five new customers in the third quarter.
<h3>Customer retention rate</h3>
It determines the percentage of customers that the company has retained over a given period.
The customer retention rate is determined by;

Substitute all the values in the formula;

Hence, there is a 96% customer retention rate for the third quarter.
To know more about customer retention rate click the link given below.
brainly.com/question/25668470