Answer:
Question 1)
Gwen has already burned 100 calories when Tristan and Keith started, and he continues to burn 10 calories per minute. The equation for Gwen is
y = 100 + 10x
Question 2)
`Tristan is burning 125 calories every 10 minutes. His burning calories rate is 12.5 calories per minute. The equation for Tristan is
y = 12.5x
Question 3)
Keith is burning 300 calories in 30 minutes. His rate per minute is 10 calories per minute. The equation for Keith is
y = 10x