Posted by Ashli on .
Lily and Sara each had an equal amount of money at first. After Lily spent $18 and Sara spent $25, Lily had twice as much as Sara. How much money did each of them have at first?
Let the amount each had initially be x.
x - 18 = 2*(x - 25) = 2x - 50
x = 32
Singapore Math -
Here is your bar model:
This is a unit bar: [xxx]
Before - the had equal amounts, then they each spent some money. In the end, Lily has twice as much as Sara, or 2 units.
If they started out the same, the second unit bar for Lily must be equal to $25 - $18, so $7
Lily had 2 units (2 x $7)+$18 at first.
Sara had 1 unit ($7)+$25 at first.