I believe the answer to question 2 is the first option, and the answer to question 3 is the last option
Answer:
Step-by-step explanation:
Much depends on how accurate an estimate you want.
If "to the nearest hundred" would be acceptable (it's a lot of work),
Round off 542817 to 542820 and 27398 to 2740. Then you'd want to subtract 2740 from 542820. (Again, it's a lot of work.)
Otherwise round off to the nearest thousand: 543000 - 27000.
Or go to the nearest ten thousand: 540,000 - 30,000 = 510,000 (estimate)
If they meet after 8 hours, then the sum of their average speeds is 600/8=75 km per hour. If one is 5 km per hour faster than the other, then if we set the speed of the slower man to x, we have:
2x+5=75
So:
2x=70
x=30
The fastest man is 5 km per hour faster than the slower, so he travels 35 km per hour.