Didn't understand test Q: x + y = 2000, 800x + 500y = 1539500

Simgre

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So, I just had a test in school and there was only one question i didn't understand. (my teacher couldn't solve this question)

The info we got was that:
x + y = 2000
800x + 500y = 1539500
And we were supposed to find out what x and y was.
Thanks in advance!
//Simgre
 
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So, I just had a test in school and there was only one question i didn't understand.

The info we got was that:
x + y = 2000 ......................................(1)
800x + 500y = 1539500 ........................(2)
And we were supposed to find out what x and y was.
Thanks in advance!
//Simgre
Which grade are you attending?

If your teacher could not solve this problem - change your teacher and quickly make complain to your school administrators.

Divide (2) by 100 and rewrite:

8x + 5y = 15395 ........................(3)

from (1)

x = 2000 - y ........................(4)

Replace 'x' in (3) to get:

8*(2000 - y) + 5y = 15395

simplify above and solve for 'y'

Use that value of 'y' in (4) - and solve for 'x'.
 
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So, I just had a test in school and there was only one question i didn't understand.
Does this mean that you have not yet studied "systems of linear equations"?

By the way, if you're being graded (that is, if this was a "for credit" question) on topics that have not yet been covered (plus your educator doesn't know what this is), then you (and your parents, if you're in middle or high school) need to have a serious talk with administration. This "educator" shouldn't be in the classroom and, if you're in college, you should maybe get your course fees refunded! :shock:
 
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