the Numbers of days = 3
The second statement(She raised $0.50 for each 1/3 of mile that she walked) means
1/3 miles = $0.50
For first day walk we have:
1/3 miles = $0.50
12 miles = 12 x 0.50 x 3 = $18
For Second day walk we have:
1/3 miles = $0.50
8miles = 8 x 0.50 x 3 = $12
For Third day walk we have:
1/3 miles = $0.50
16miles = 16 x 0.50 x 3 = $24
The amount she raised for the three days becomes
$18 + $12 + $24
=$54