you have $28.00 in your bank account and start saving $18.25 every week. Your friend has $161.00 in his account and is withdrawing $15 every week. When will you

Question

I am having issues with this problem. We didnt go over one like this in class, and I'm super confused. 

Answer 1

The amount of dollars in your bank account can be represented by the variable "d", and the number of weeks after the start of the problem can be represented using "w"

 

At first, you have $28.00 in your bank account.

After 1 week, you have 28.00 + 18.25 = $46.25

After 2 weeks, you have 28.00 + 18.25 + 18.25 = $64.50

 

This relationship can be written as 28.00 + 18.25 * w = d

 

Likewise, your friend's bank account can be thought of as 

161.00 - 15.00*w = d

 

We want to see at what week will you have the same amount of money in the account. (By the way, if the entire question doesn't fit in the subject, please include the rest in the description.)

 

To do this, we set the two equations equal to each other, because we know that the variable "d" in each equation is the same.

 

28.00 + 18.25*w = 161.00 - 15.00*w

 

Add 15.00*w to both sides

28.00 + 33.25*w = 161.00

 

Subtract 28.00 from both sides

33.25*w = 133

 

Divide both sides by 33.25

w = 4

 

After 4 weeks, you and your friend will have the same amount of money in your bank accounts.