SOLUTION: Use any suitable method to find the sum of 63+68+73+...+103+108

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Question 1056567: Use any suitable method to find the sum of
63+68+73+...+103+108
Found 2 solutions by ikleyn, MathTherapy:
Answer by ikleyn(52790)   (Show Source):
You can put this solution on YOUR website!
.
Use any suitable method to find the sum of
63+68+73+...+103+108
~~~~~~~~~~~~~~~~~~~~~~~~~~

Arithmetic progression with the common difference 5.

The number of terms is + 1 = 10.

The sum is = 855.

I used the formula for the sum of an arithmetic progression.

See the lessons
    - Arithmetic progressions
    - The proofs of the formulas for arithmetic progressions
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Answer by MathTherapy(10552)   (Show Source):
You can put this solution on YOUR website!
Use any suitable method to find the sum of
63+68+73+...+103+108

Number of terms (n) in the sequence: , where: is the last term is the 1st term d is the common difference

now becomes: _____
n, or number of terms = 9 + 1, or 10
Sum of an AP formula:
____
Sum of the AP, or