Final answer:
The equation that best represents Ash's routine is 35x-20y=340.
Step-by-step explanation:
The equation that best represents Ash's routine is 35x-20y=340.
The question states that for every minute Ash walks, she burns 20 calories, and for every minute she cycles, she burns 35 calories. The equation represents the calories burned from walking (20x) subtracted from the calories burned from cycling (35y), equaling 340 calories burned in total. Therefore, the correct equation is 35x-20y=340.