Part a- katelyn and travis go on a trip. when they start out, their odometer reads 34,118 miles. if they drive 320 miles the first day, what will the reading on their odometer be? answer-34,438

part b- katelyn and travis forgot to write down the mileage on the second day, but after the third day their odometer read 34,963 miles what was the average number of miles they drove during the second and third day? answer 525 miles

i’m confused on part c. i need figuring out how to do it!

part c- at the end of the third day, katelynn and travis reached their destination. they spent 4 days at their destination and then they drove home. if it only took then 2 days to drive home, what was their average number of miles driven each day, assuming they followed the same route home with no side trips?

show work so i understand! i’m not about just wanting answers, but wanting to know how you got the answer you did.