I'm terrible at math, so I'm sorry if I'm totally wrong, but I'm assuming you just take the average:
20+28=48m
48/2=24m
On average, it may take them 24m if they work together.
Answer:
12(3+5)
Step-by-step explanation:
The greatest common factor is 12
12*3 + 12*5
12(3+5)
The greatest common factor of those numbers is 8.
Answer: 
Step-by-step explanation:
First, we need to find the common denominator
The easiest way to do this is by multiplying the two given denominators, which are 2 and 5.
2 × 5 = 10
So, our common denominator is 10. Then, multiply the numerators of the two fractions by 2 and 5. Here's why:
=
We multiplied the top and bottom by 2 to make sure our new fraction stays equivalent to the original fraction.
Do the same thing for the other one:
= 
Finally, subtract the two fractions to find the difference between the two times:
= 
The reason we used the common denominator is because we can only add or subtract fractions if they have the same denominator.
Answer:
5x + y = 8
Step-by-step explanation:
Given the equations:
x+3y=10 ____ (1)
2x−y=−1 ____ (2)
Multiply (2) by 2
2(2x - y = - 1) = 4x - 2y = - 2
4x - 2y = - 2 - - - (3)
Add (1) and (3)
4x - 2y = - 2
x + 3y = 10
___________
5x + y = 8
_________