For this exercise you need to remember that a percent can be written as a Decimal number by dividing it by 100.
• You know that he spends 30% on rent and 10% on utilities, this gives a total of 40%. This percent written as a Decimal number, is:

After the pay these things, the amount of money left is:

• Since he saves 5% of his pay each month, the amount of money left is:

• The amount of money left after he gives money to the charity, is:

Knowing the above, you can calculate the amount of money left for other purposes as following:

The amount of money left for other purposes, is:
