Answer: 4 9/20
Step-by-step explanation: Since it is 20km/h, and it is 25km, you can find 1/4th of 20, which is 5, and add it because 25 is 1 1/4 of 20, he traveled 1 1/4 hours on the first session, and then he goes and does 80km. same thing, exept it is a lot bigger than 25km/h, and the fact that the cyclist is faster by 5km/h. so then, you can multiply to get the closest number which is not greater than 80, which is 75. so we know it is around 3 hours, so since it is 5 km, and 25 km is faster than 20km, it is going to be 1/5th of an hour extra. so 3 1/5 hours + 1 1/4 hours is 4 9/20. I cannot simplify because it is already a mixed number, and there is no LCM between 9 and 20. so that's it.
Sorry if I extremely overexplained.
