Thomas won $16,000 on a game show, and he put all of the money in a checking account (which does not give interest). Each month, he takes $400 out of the account for "spending" money.

The equation that describes this situation is M=16000−400t
, where t
is the time in months since opening the account, and M
is the amount of money left in the account.

In how many months will Thomas empty the account (which means that there will be no money left)?