Summations Problem: Sum of Multiples of 5 from 5-1550

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The discussion focuses on calculating the sum of all whole numbers that are multiples of 5 from 5 to 1550. The correct approach involves recognizing that there are 310 multiples of 5 in this range, derived from dividing 1550 by 5. A hint suggests using the formula for the sum of an arithmetic progression, specifically 5 times the sum of the first 310 integers. There is confusion regarding the calculations, particularly with the order of operations leading to incorrect results. Ultimately, the correct sum is derived from the proper application of the arithmetic series formula.
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Homework Statement


Sum all the whole numbers which are multiples of 5 from 5 to 1550


Homework Equations





The Attempt at a Solution


1550÷5=310
1550-5x310= 478950
 
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elainehula said:

Homework Statement


Sum all the whole numbers which are multiples of 5 from 5 to 1550


Homework Equations





The Attempt at a Solution


1550÷5=310
1550-5x310= 478950

Hint: Sum of arithmetic progression or, alternatively,$$
\sum_{k=1}^{310}5k = 5\sum_{k=1}^{310}k$$
 
elainehula said:

Homework Statement


Sum all the whole numbers which are multiples of 5 from 5 to 1550


Homework Equations





The Attempt at a Solution


1550÷5=310
Yes, that is correct

1550-5x310= 478950
No, 1550- 5x 310= 0, That is what 1550÷5= 310 means!
 
HallsofIvy said:
Yes, that is correct


No, 1550- 5x 310= 0, That is what 1550÷5= 310 means!

She is using the parentheses differently (incorrectly so , by priority of operations):

1550-5=1545 , 1545x310= 474950
 

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