Tom earns $30 a week mowing lawns. He spends one-tenth of his earnings on lunch and one-fifth of his earnings on music. He saves the rest. How many dollars does Tom save? Tell me how you found the answer.

Tom saves $21

Step-by-step explanation: The monthly earning has been given as $30. The spendings are expressed as fractions of the total earnings. The expenses are as follows;

Lunch = one tenth of the earnings

Lunch = 1/10 x 30

Lunch = 30/10

Lunch = 3

Also he spends the following on music

Music = one fifth of the earnings

Music = 1/5 x 30

Music = 30/5

Music = 6

So he spends a total of 3 plus 6 which equals 9 dollars out of his earnings. His savings becomes

Savings = 30 - 9

Savings = 21

Therefore his savings is $21