Final answer:
Sam has $400 left, and he spent $400 on the watch and bed.
Step-by-step explanation:
To find out how much money Sam has, let's first calculate how much money Max has. Max initially received $500, and 2 minutes later, he has $400 more than Sam. Therefore, Max has $500 + $400 = $900.
Since Sam has $100 less than Max, he has $900 - $100 = $800.
Now let's calculate how much money Sam spent on the watch and bed. If Sam has $800 initially, and he spent $400 on the watch and bed, then he has $800 - $400 = $400 left.
Therefore, Sam has $400 left, and he spent $400 on the watch and bed.