Find six rational numbers between 8 and 9

The graph shows the distance kerri drives on a trip. what is kerri's speed?

Starting at home, emily traveled uphill to the hardware store for 606060 minutes at just 666 mph. she then traveled back home along the same path downhill at a speed of 121212 mph. what is her average speed for the entire trip from home to the hardware store and back?

Prove that 16^4-2^13-4^5 is divisible by 11.