 
 <translate> Give the step-by-step reasoning process and then the final answer. Greg has his own dog walking business. He charges $20 per dog plus $1 per minute per dog for walking the dog. If he walks one dog for 10 minutes, two dogs for 7 minutes and three dogs for 9 minutes, how much money, in dollars, does he earn? <hau> Bayyana tsarin tunani mataki-mataki sannan kuma amsar karshe. Greg yana da kasuwancinsa na yawo da karnuka. Yana cajin $20 ga kowane kare da $1 a minti daya ga kowane kare da yake yawo da shi. Idan ya yi tafiya da kare guda na minti 10, biyu na minti 7, da uku na minti 9, nawa ne zai samu a dala? 