description

Question

Kira is saving money to buy a bike that costs
$133
. She has
$42
and will save an additional
$7
each week. In how many weeks will she have enough money to buy the bike?

Answer 1

$133 = $42 + 91;  the $91 is to be accumulated at $7 per week.

Divide 7 into 91 to find how many weeks it takes to get the necessary total.

Answer 2

Okay, so let's look at what you know, shall we? 

You know how much the bike costs, correct? $133.00
And, you also know how much Kira already has, correct? $42.00
Finally, you know how much she will save each additional week, correct? $7.00 

Now, you can set up an equation, understanding the ONLY thing you do not know is "how many weeks" it will take for Kira to save enough money to buy her bike. 

Therefore, 

42 + 7(x) = 133

Remember, whatever you do on one side of an equation, you MUST do on the other. 

So, you can subtract 42 from the left side of the equation and on the right leaving you with the following: 

7(x) = 91

Now, to simplify, all you need to is divide 7 into 91 in order to leave x to itself. 

Once you do this, you are left with: 

x = 13 

Remember x was what is unknown, and due to the equation you now know it will take 13 weeks to save enough money for Kira to buy the bike. To proof your work, you can simply plug 13 into the x from the original equation. 

The original equation was: 

42 + 7(x) = 133
Plug the value of 13 in for x now. 

42 + 7(13) = 133  

Remember BODMAS  Brackets, powers, division, multiplication, addition, and subtraction.  Therefore:

42 + 91 =133 

When you do your addition on the left it indeed, equals the right. I hope I have assisted you beyond just answering the question.