SOLUTION: In April, Bob changed 1140 Indian Rupees into German Marks when the rate of exchange was x Rupees = 1 Mark. In August, he again changed 1140 Rupees into Marks. The rate of exchange

Question 1018734: In April, Bob changed 1140 Indian Rupees into German Marks when the rate of exchange was x Rupees = 1 Mark. In August, he again changed 1140 Rupees into Marks. The rate of exchange was then (x+1) Rupees = 1 Mark. He received 3 Marks less in April than he did in August. Solve the equation: x^2 + x - 380 = 0 to find the rate of exchange in April.
How? I understand the equation and everything else, but I am just stuck on the last bit of the question. How do you do this?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
In April, Bob will receive Marks according to:

In August, he received Marks according to:

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He received 3 Marks less in April than he did in August.
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Multiply both sides by

I get a different equation ( sign of 380 )
I'll use the one they gave:
----------------------------------
Use quadratic formula

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The rate in April was 19 Rupees = 1 Mark
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I looked over my algebra, and I don't see why I
got a different equation. Their's work and mine doesn't
Can you see my mistake?
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