Janet and Jack are walking in a two-day event to raise money for charity. Janet asks a friend for a $7.50 donation, plus $0.10 for each mile she walks. Jack asks a friend for a $5.50 donation, plus $0.15 for each mile he walks. At how many miles of walking would Janet and Jack collect the same amount of money?
A. 44
B. 40
C. 28
D. 25