Question

Rational Equations

Problem: Abby alone requires 6 hours to map the area, Brian takes 8 hours, and Charles only 4 hours. how long would it take for the 3 to do the mapping

Problem:
Solution:
Final answer:

Useless answer report

Answer 1

Answer:

24/3 hours

Step-by-step explanation:

assuming the work speed of these 3 people are

a, b, c, (per hour)

So ba=8b=4c=M

T= M/a+b+c = M/ m/b+ m/8+m/4= 24/13 hours

Answer 2

Answer:

$\frac{24}{13} \ [hour].$

Step-by-step explanation:

1) if all the work is 1, then the performance/efficiency/productivity for Abby is 1/6, for Brian is 1/8 and for Charles is 1/4;

2) if the performance/efficiency/productivity are 1/6; 1/8 and 1/4, then it is possible to make up for all work was done ('t' - required time):

$(\frac{1}{6} +\frac{1}{8} +\frac{1}{4} )*t=1;$

3) if to solve the equation above, then t=24/13 [hour]≈111 [min].

P.S. the suggested solution is not the only, there are several ways to solve this task.