It takes leon 13 hours to seal his driveway working by hinself. If michael helps leon, they can seal the driveway in 7 hours. How long would it take michael to seal yhe drive way alone?

15.1667 hours (15 hours and 10 minutes)

Step-by-step explanation:

Using the concept of "distance = speed * time", we can formulate equations to solve this problem.

Let's call Leon's speed X, Michael's speed Y and the length of the driveway D.

If leon takes 13 hours alone, we can write the equation:

D = X * 13

If Michael helps Leon, we have this equation:

D = (X+Y) * 7

(The total speed is the sum of their speed, as they are working together)

Making the first equation equate the second, we have:

13*X = 7*X + 7*Y

7*Y = 6*X

X = (7/6)*Y

If we use this value of X in the first equation, we have:

D = 13*X = 13*(7/6)*Y = 15.1667*Y

So we have that Michael would take 15.1667 hours (15 hours and 10 minutes) to seal the driveway alone.

the simplified form is

step-by-step explanation:

we want to simplify the expression,

let us change the middle bar to a normal division sign to obtain,

we multiply the first fraction by the reciprocal of the second fraction to obtain,

we factor to obtain,

we cancel the common factors to get,

we simplify to get,

the correct answer is b