SOLUTION: 7. Find the sum of a) the positive multiples of 5 up to 500 b) the positive multiples of 7 up to 245

Question 1187218: 7. Find the sum of
a) the positive multiples of 5 up to 500
b) the positive multiples of 7 up to 245

Answer by ikleyn(52790) (Show Source): You can put this solution on YOUR website!
.
7. Find the sum of
a) the positive multiples of 5 up to 500
b) the positive multiples of 7 up to 245
~~~~~~~~~~~~~~~`

(a)  S = 5 + 10 + 15 + . . . + 500 = 5*(1 + 2 + 3 + . . . + 100) =  = 5*50*101 = 25250.    ANSWER


     Use the formula of the sum of the first n natural numbers  1 + 2 + 3 + . . . + n = .

Part (a) is just solved.

Do part (b) in the same way.

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