Need help setting up word problem formula

Question

the problem is as follows, I don't know what the formula should look like. 

 

Mary has been saving her money. She has $69.00 consisting of $5 bills and $1 bills. If she has a total of 25 bills, how many $5 and how many $1 bills does she have?

Answer 1

All you ever do in these problems is translate the sentences given into equivalent equations, after first deciding what unknowns you have.  Let f = number of $5 bills, let b = number of $1 bills.  So f + b = 25.

Then write the value equation: 5f + 1b = 69.  That is, each of the "f" fivers is worth $5, each of the "b" bills is worth $1.

 

Now, solve this (surely they've been doing this type of thing in your Algebra class).

 

 

 

 

Answer 2

Hi Mark,

 

If there x $5 bills and y $1 bills,

 

x(multiply by $5) + y (multiply by $1) = $69

5x + y = 69

  x + y = 25