SOLUTION: How would you work the problem, "On a recent day, 8 euros were worth $9 and 40 euros were worth $45. Enter an equation of the form y = kx to show the relationship between the numbe

Algebra ->  Proportions  -> Lessons -> SOLUTION: How would you work the problem, "On a recent day, 8 euros were worth $9 and 40 euros were worth $45. Enter an equation of the form y = kx to show the relationship between the numbe      Log On


   

Question 991981: How would you work the problem, "On a recent day, 8 euros were worth $9 and 40 euros were worth $45. Enter an equation of the form y = kx to show the relationship between the number of euros and the value in dollars. Let y be the value in dollars and x be the number of euros." Thank you for the help." My mom tried to tell me a way on if y=9 then i would multiply 9 and 9 but i haven't learned how to do that yet. Can you please help me work it out?
Found 2 solutions by josmiceli, macston:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+y+ = dollars
+x+ = euros
--------------
+y+=+k%2Ax+
+9+=+k%2A8+
Divide both sides by +8+
+k+=+9%2F8+
--------------
The equation is
+y+=+%289%2F8%29%2Ax+
----------------
Check:
+y+=+45+
+x+=+40+
+45+=+%289%2F8%29%2A40+
Divide both sides by +40+
+45%2F40+=+9%2F8+
Divide the top and bottom of the left side by +5+
+9%2F8+=+9%2F8+
OK

Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
What are you trying to work out?
.
y=value in dollars, x=number of euros
.
y=kx , Put in values for x and y
$9=k(€8)
$9/€8=k
$1.125/€=k
.
"k" is the exchange rate, dollars per euro.
We can check with the sample example.
.
€40=$45:
.
y=kx
$45=($1.125/€)(€40)
$45=$45
.