Answer:
$39 is the correct answer .
Step-by-step explanation:
Let the amount he earned on the afternoon be x then
Amount earned in morning + Amount earned in afternoon=total amount
[tex]\$ 21 +\ x\ =\ \$ 60 \\\ x=\$60 -\$ 21\\x=\$ 39[/tex]
Therefore $39 is the amount he earned on afternoon .
