For this case we have:
G: Let the variable representing the amount of initial money in the account.
If you spend [tex]\frac {1} {3}[/tex]of G then we have:
[tex]G (1- \frac {1} {3}) = G (\frac {3-1} {3}) = \frac {2} {3} G[/tex]
Then spend $20, then we have:
[tex]\frac {2} {3} G-20[/tex]
Finally, the expression that represents the money left in the account is:
[tex]\frac {2} {3} G-20[/tex]
Answer:
[tex]\frac {2} {3} G-20[/tex]
