Question 25

Friday, November 6, 2009
Hello there everyone! Nicky here to answer question 25 from the math textbook. Here's the question in case you don't remember it:

Create a word problem that involves operations with rational numbers in decimal form. Make sure you can solve your problem. Then, have a classmate solve your problem.

Do my eyes deceive me or do I get to make a math problem? Yay! I've always wanted to make one of these... Hm... Lets see... What should it be about... Ah! I know, a little boy... His name is Billy Jenkins... Here's the question in full:

Part A) Billy Jenkins is a little boy. Being a little boy, Billy Jenkins likes to play with toy cars. Everyday he plays with his red car for 3.8 hours and then plays with his blue car for 125 minutes. How many hours (expressed in decimal form) does Billy play with his cars each day?

Part B) Billy's friend Bobby also likes to play with toy cars. However, Bobby makes loud noises when he plays with Billy, distracting him. On average, Bobby annoys Billy for half an hour each day. Knowing this, how much time does Billy actually get to play with his toy cars?

Part C) Now Billy is a mathematician, who thinks all smarticle. One day, he remembered that when he was young he liked to play with his toy cars. He remembers playing with them for 2 years under the same pattern. How many hours did Billy play with his toy cars during those 2 years?

Now isn't that a mouthful? However, it can be solved quite easily as you will soon see. We will start with Part A.

So, we know that Billy plays with his red car for 3.8 hours and that he plays with his blue car for 125 minutes each day. So, we must first convert both of the values into hours. So, how many hours are in 125 minutes? Well, there are 60 minutes in an hour so there are at least 2 hours in 125 minutes (60+60=120) but what about those 5 minutes? Well, we need to figure out what fraction of 60 minutes 5 minutes is. So, we can always use a ratio table like the one below...

So, now that we have our two numbers (3.8 hours and 2.083) we just have to add them together which gives us a sum of 5.883 (repeating). Now, on to Part B.

So, we know that Bobby annoys Billy for half an hour each day and that Billy plays for 5.883 hours each day. So, we must first convert those minutes into hours. That would translate to 30 minutes or 0.5 hours. Now, all we have to do is subtract 0.5 from 5.883 which would give us a difference of 5.383. We're almost there! To Part C we go!
Okay... So now Billy is a mathematician and he (because he's a mathematician) thinks about math all day long. And one day (for whatever reason) he remembered that he used to play with cars as a little boy. And then he remembered he played in that same pattern for 2 whole years... So, we must now get to solving this problem...
Now, Billy said he played for 5.383 hours each day for 2 years. So, we must first figure out how many days are in 1 year, which is 365 days. Which means 2 years have 730 days. Now it is a simple matter of multiplying 5.383 by 730 which gives us a product of 3929.59.
There you go everyone, my rational numbers word problem. Feel free to comment and suggest improvements for both my post itself and maybe even my questions.

Vikram 9-05 said...

Hey Nicky, you have a nice post going on there. I just noticed a few grammar errors and that's all. Good job!

Lissa 9-05 said...

Hi Nicky! Woah, you wrote so much on your scribe post! Well done! I suggest you use pictures next time (:

Austin 9-05 said...

Whats up Nicky? You explained everything so clearly. But like what Vikram said, there are a few spelling mistakes but other than that, you did an awesome job! :D