Carlor's Scribe post: Textbook pages 142-143

Hey everyone! this scribe post will be about the solutions for numbers 4,7, and 11 on pages 142-143 chapter 4.3.


4.)
- For this questions it says that use your mental math to solve them so please try to trust your brain first rather than your finger.


- You can do solve these questions the fast way but for now let's do the slower way so that it is more understandable.

A.)
-For this question it's asking for the 20% of 60, so first we need to find 10 %.


- Now we know that 6 is 10% of 60 but what we're looking for is 20% so we need to multiply by 2 or you can also add by 6.

- So there it is we found 20% of 60 which is 12.

B.)
- For this question they are asking for 250% of 400 but, we know 400 is equal to 100% so we only need to double that to get 200% which would be 800. So, now the problem is 50%.
And all we have to do is divide it by 2.

- Now we know all the parts of our percent, we only need to add all them up.
800+200= 1,000 so, there it is 250% of 400 is 1,000!

C.)
- For this question it's asking us for 10.5% of 100. We know that 10% of 100 is 10 so we only have to find 0.50% of 100. In order to find it we have to find 1% in which we would divide by 2 to get 0.5%


- Hey, it's 1! so we divide it by 2 to get 0.5% which would be 0.5. And all we have to do is add up- 10+0.50= 10.5. There it is 10.5% of 100 is 10.5 they're the same!

7.)



A.)
- This question is asking what are the chances of winning with one ticket and expressing them in percents.So, we need to use this formula to get the percent or chance = (amount divided by total)x100= percentage

Because we are finding the chances of one ticket we need to set that (1 ticket as the amount and divide it by 200 as the total tickets sold) and multiply it by 100= percentage or the chances.

1st-
2nd-


- Woah! There it is the chance of winning with one ticket is only 0.5%.

B.)
- For this question we need to find how many tickets we have to buy to get 2.5% of winning.
- But, we already know that 1 ticket have a 0.5% chance winning.
- So we only need to find what 2.5% percent would equal to.



Answer- It's 5!

11.)

- For this question they are looking for 6.5% of 9 984 670 square kilometre.
- So we need to find 1% and add it to get 6% next, we need to find 0.5% and add it all up.


- Now we know that 1% is 99846.7, we need to multiply that to get 6% which would be 599,080.2.
- Our problem now is 0.5 so we will find it.
- It's 49937.35! So we add it all up 599,080.2 + 49937.35= 649017.55!

- That's it! 649017.55 squared kilometre is the area of Manitoba compared to the area of Canada.

Here is a video which demonstrates more about how to get percent of a number. Enjoy!





Link to mess with percents: http://www.mathplayground.com/balloon_invaders_percent.html

That's the end of my post and Thanks for viewing!

I'm sorry I posted it up really late! I'm really sorry guys :/