# Error

**URL:** <https://community.blackspectacles.com/t/error/2826>\
**Category:** Practice Management\
**Created:** [March 31, 2021, 2:16am UTC](https://community.blackspectacles.com/t/error/2826 "2021-03-31T02:16:48Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![carlos11937](https://blackspectacles.com/uploads/images/10.png) [@carlos11937](https://community.blackspectacles.com/u/carlos11937)\
**Post date:** [March 31, 2021, 2:16am UTC](https://community.blackspectacles.com/t/error/2826/1 "2021-03-31T02:16:48Z")

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This is found by using the cost of the work estimate given in the architect’s memo, which is $19,500,000. We need to find the cost per square foot, so divide the total cost by the number of square feet given in the memo, which is 52,000 square feet:

$19,500,000 / 52,000 sf = $375/sf

If we increase the square footage by 10%, we get:

1.10 \* 52,000 sf = 57,200 sf

We then multiply that by the cost per square foot we just found:

57,200 sf \* $375/sf = $21,450,000

And add on the extra $15,000 for the finish change:

$21,450,000 + $15,000 = $21,465,000

ERROR 10%=.01 NOT 1.10

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**Author:** ![monicafitzpatrick](https://blackspectacles.com/uploads/images/1.png) [@monicafitzpatrick](https://community.blackspectacles.com/u/monicafitzpatrick)\
**Post date:** [April 8, 2021, 8:41pm UTC](https://community.blackspectacles.com/t/error/2826/2 "2021-04-08T20:41:17Z")

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Hello!

@coachchrishopstock do you mind looking into this?

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**Author:** ![coachchrishopstock](https://yyz1.discourse-cdn.com/flex029/user_avatar/community.blackspectacles.com/coachchrishopstock/32/1662_2.png) [@coachchrishopstock](https://community.blackspectacles.com/u/coachchrishopstock)\
**Post date:** [April 8, 2021, 9:42pm UTC](https://community.blackspectacles.com/t/error/2826/3 "2021-04-08T21:42:59Z")

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Hi @carlos11937 - The question says that the square footage has been increased by 10%, so a quick way to do that math is to multiply the current square footage by 1.10.  
Another way to do it would be to multiply by 0.1, then add that to the original square footage.  
Either way, you’d ultimately arrive at the same answer, which is $21,465,000 for this question.  
I hope this was helpful!

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**Author:** ![carlos11937](https://blackspectacles.com/uploads/images/10.png) [@carlos11937](https://community.blackspectacles.com/u/carlos11937)\
**Post date:** [April 9, 2021, 11:02am UTC](https://community.blackspectacles.com/t/error/2826/4 "2021-04-09T11:02:02Z")

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But how do you get 1.10 if 10% = 0.10

**E-MAIL TO CONFIRM**

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**Author:** ![coachchrishopstock](https://yyz1.discourse-cdn.com/flex029/user_avatar/community.blackspectacles.com/coachchrishopstock/32/1662_2.png) [@coachchrishopstock](https://community.blackspectacles.com/u/coachchrishopstock)\
**Post date:** [April 9, 2021, 1:38pm UTC](https://community.blackspectacles.com/t/error/2826/5 "2021-04-09T13:38:41Z")

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Hey @carlos11937 -  
Just to reiterate, the question is stating that the square footage was **increased** by 10%, not that we must find 10% of the current square footage. Therefore, we can multiply the current square footage by 1.1 to find the increased square footage.

A simpler example, using a 20% increase instead: A bedroom is 100 square feet, what would the size be if we increased it by 20%?  
We can do it two ways:  
100sf x .20 = 20sf  
100sf + 20sf = 120sf

Or, simply:  
100sf x 1.2 = 120sf