Saturday, January 23, 2010

Finance Problem 1 Solution

This is the solution to the algebra finance word problem that An anonymous poster recently asked which read:

"An employee's new salary is $19,110 after getting a 5% raise. What was the salary before the increase in pay?"

Ok easiest way to think about this is try something you do know for sure. Whats 5% of 100? 5 right--- Ok, so what if the problem said an employee's new salary was $105 after a 5% increase in pay what was the salary before... Ok you already know the answer 100.... So how would u come up with the new total? Well 5% of 100 is 5 and then you add it to the original amount of 100 which makes 105. So, you set up your problem like that:

5% can be written 5/100

so,

5/100 * x + x = 105 multiply by 100

5 * x + 100x = 10500

5x + 100x = 10500

105x = 10500
x = 10500/105 = 100 so 100 is the answer you were looking for and it checks out..

You solve this problem exactly the same way.

5/100 * x + x = 19110 multiply by 100

5x + 100x = 1911000

105x = 1911000

1911000/105 = x

x = 18200 So check whats 5% of 18200 ? its 910 Now add 910 to 18200 and you get 19110. So it checks out.




Sunday, January 10, 2010

Time and Distance Problem 11 Solution

This is the answer to the algebra time and distance word problem #11 which was asked by another anonymous user on the "Algebra Word Problem Questions" post. The question read:

"Alexis left Miami and drove at a speed of 20 kph. Thomas left 3 hours later, from the same point, and drove at a speed of 30 kph. How long will it take Thomas to catch up to Alexis?"


Ok non-algebraically the easiest way to figure this one out is to figure how far kilometers Alexis has gone before Thomas even leaves. Since Thomas left 3 hours later and Alexis drove 20 kph then Alexis has gone 20(3) or 60 k or kilometers. Thomas is going faster but how much faster than Alexis? (30 - 20)kmh = 10 So, the question is if he's creeping up at 10 kmh how long would it take him to go the distance that Alexis is ahead which we figured out to be 60 kilometers. Well at 10 kph it would take 6 hours to to 60 k... 60 k / 10 kph = 6 h

For the algebra way you just set up the equation where you have :

20(3 + x) = 30x --> the time is x + 3 because she had a 3 hour head start

then you have 60 + 20x = 30x

60 = `10x

x = 60/10 = 6 --> 6 hours






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