Saturday, November 3, 2012

Textbook: pg.68 question 9 and 10


9. Lori owed her mother $39. Lori paid back 1/3 of this debt and then paid back 1/4 of the remaining debt.
     How much does Lori still owe her mother?

  • we can represent $39 just as 39
  • 1/3 and 1/4 can be -1/3 and -1/4 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~







That multiply suppose to be addition..
Lori then pay back 1/4 of the remaining debt...

 















Lori still owes her mother $19.50.

 10. A carpenter has 64m of baseboard. He installs 1/2 of the baseboard in one room. He installs another 3/5 of the original amount of baseboard in another room. How much baseboard does he have left? 

 64m =64
1/2 and 3/4 can be -1/2 -3/5 

-1/2 x 64

= -1/2 x 64/1 
=-64/2
= -32  

-3/5 x 64 

=-3/5 x 64/1 
=-192/5 
= -38.4 

 -32 + (-38.9) = -70.4   <---- how much was installed 

64 + (-70.4) = 6.4    <----- how much he has left

The carpenter has to install 6.4m more of the baseboard

  













No comments:

Post a Comment