Brian can lay a slab of concrete in 6 hours, while greg can do it in 4 hours. if brian and greg work together, how long will it take?

Step-by-step explanation:

we know that

step 1

Brian can lay a slab of concrete in 6 hours

so

The 100% -------> in 6 hours

using proportion

Find in an hour how much percentage  Brian can execute

step 2

Greg can lay a slab of concrete in 4 hours

so

The 100% -------> in 4 hours

using proportion

Find in an hour how much percentage  Greg can execute

step 3

we know that

In one hour (Brian and Greg) execute (16.67%+25%)=41.67%

so

by proportion

Find out how long it will take Brian and Greg to lay a concrete slab working together

its a little blurry tbh

step-by-step explanation:

8

step-by-step explanation: