There were 143 more Susan B. Anthony dollars than there were quarter. If the total value of the coins was $153, how many Susan B. Anthony dollars were there?

Question

Once this is set up I’m supposed to use elimination to solve it, but I don’t know how to set this up...

Answer 1

Joshua, here's how to set up word problems like this:

First, identify all the quantities involved:

 

Let d be the number of dollars

Let q be the number of quarters

 

Next, translate the words into formulas that relate those quantities:

 

(more dollars than quarters)

d = 143 + q

(total value of all coins)

1.00 * d + .25 * q = 153

 

Third, you know the two equations, and you want to eliminate one of them. In this case, you know what "d" is, so SUBSTITUTE (143+q) into the other equation in place of "d"

 

1.00 *(143+q) + .25*q = 153

 

Now you have only one equation, and only one unknown (q). You have successfullly eliminated d! Solve for q .

Once you have a numerical value for q, substitute it back into "d=143+q", and solve for d.