Find the sum of the first 18 terms of the arithmetic sequence whose nth term is an = 3n - 1.

495

Step-by-step explanation:

In order to find the sum of the first 18 terms you have to find the 18th term and the first term using the equation given.

a1=3(1)-1        a1=2

a18=3(18)-1   a18= 53

Then plug in 53 for an, 18 for n, and 2 in for a1 in the sum equation: Sn=n/2(a1+an)  

Sn=18/2(2+53)  Solve for sn= 495

step-by-step explanation:

; fx

step-by-step explanation:

*calories burned = (weight)(calorie factor)*

calories burned = 180 (0.65)

calories burned = 117

the calories he used up is 117, which is 65% of his weight.