SOLUTION: i have x N5 notes and y N10 notes. there are eight notes altogether and their total value is N55.how many of each notes do i have?

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Question 1071362: i have x N5 notes and y N10 notes. there are eight notes altogether and their total value is N55.how many of each notes do i have?
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
Translation into Algebreze:
x%2By=8 because "there are eight notes altogether."
5x%2B10y=55 because "their total value is N55."

SOLUTION BY SUBSTITUTION:
system%28x%2By=8%2C5x%2B10y=55%29 --> system%28x=8-y%2C5x%2B10y=55%29 --> system%28x=8-y%2C5%288-y%29%2B10y=55%29 --> system%28x=8-y%2C40-5y%2B10y=55%29 --> system%28x=8-y%2C40%2B5y=55%29 --> system%28x=8-y%2C5y=55-40%29 --> system%28x=8-y%2C5y=15%29 --> system%28x=8-y%2Cy=15%2F5%29 --> system%28x=8-y%2Cy=3%29 --> system%28x=8-3%2Cy=3%29 --> highlight%28system%28x=5%2Cy=3%29%29

A SMARTER WAY:
Simplify first, like this
5x%2B10y=55 --> %285x%2B10y%29%2F5=55%2F5 --> x%2B2y=11

THE FIFTH GRADER'S SOLUTION:
N5 notes are better because if you only carry one N5 note,
I cannot be tempted to spend N10 at one time.
I should change those N10 notes,
trading each N10 note for 2 N5 notes.
I will have the same amount of money,
but for each N10 note I get changed, I will have one more note.
I will still have N55,
but I will have 55%2F5=11 notes rather than 8 .
That would mean that I would have changed 11-8=3 N10 notes.
So I have highlight%283%29 N10 notes,
and 8-3=highlight%285%29 N5 notes.