Answer:
5 hours
Step-by-step explanation:
We can write a ratio
20 laps 100 laps
-------------- = --------------
1 hour x hours
Using cross products
20x = 100
Divide by 20
20x/20 = 100/20
x = 5 hours
X = √7²+4² by using Pythagoras Theory as the triangle is a right angled triangle
A,81 because if you try checking 81 will be the only composite number im in 6 grade.....