Tim spent 90 minutes completing his chores. if 40% of this time he was cleaning, how many minutes did he spend not cleaning?

If he spent 40% of his time cleaning, that means he spent 60% of his time not cleaning and to find out how many minutes that is you find 60% of 90 minutes which is 90 x. 6 which equals 54 minutes

Since 40% of 90 is equivalent to 36, you have to subtract 90 and 36 to find out how many minutes he spent without cleaning, which would be 54 minutes that he spent not cleaning.