Joe had $40. He spent $4 on food. What percentage of his money did he spend on food?
To find the percentage of his money that Joe spent on food, we need to divide the amount he spent on food by the total amount he had and then multiply by 100%:
($4 / $40) * 100% = <<(4/40)*100=10>>10%
So, Joe spent 10% of his money on food.