I have several bikes and I like to ride in the morning for exercise. I am not a pro athelete by any means. But I have a time slot in which to ride before work, and I log my workouts with an application on my smartphone. Subjectively, I know how much effort I've put in during a given 30-45 min ride, and I think we all know that we have good and bad days based on our rest, stress level, how hard we rode the previous day, etc.
Long story short -- whoops, too late for that
-- it is very, very easy to see that for a given amount of time and a similar (not same!) amount of effort I go faster and farther on a road bike than my hybrid and my hybrid is faster than my MTB. Tire width, tread and bicycle weight is a massive factor. My MTB has 26x2.2 Speed King tires and they are slow and noisy on the road. My hybrid has 700x35 Cyclocross and they are much better on the road, but not nearly as good in serious dirt. My road bike has 700x23 slicks and they are a different world... plus the bike weighs less than half what the MTB weighs.