Let x = the total number of pennies her piggy bank can hold.
Then 2/3x = the number of pennies she started with
Then 2/3x - 80 = the number of pennies she has left after taking out 80 pennies.
Then 1/2x = the number of pennies she has left after taking out 80 pennies.
Build the equation.
2/3x - 80 = 1/2x
Subtract 1/2x from each side of the equation.
(2/3x - 80) - 1/2x = 1/2x - 1/2x
1/6x - 80 = 0
Add 80 to both sides of the equation.
(1/6x - 80) + 80 = 0 + 80
1/6x = 80
Divide both sides by 1/6.
(1/6x) / 1/6 = 80 / 1/6
x = 480
So, Linda's piggy bank can hold 480 pennies!
