Answer:

Step-by-step explanation:
Maybe you have ...

Then ...

The average is 80*
80* + 80*=160 divided by 2 is 80*
Jen take x hours.
Carl (x-3)hours.
Jen+carl take two hours;
This means;
In 1 hour, for they work

=

=

Working together, they take two hours;
Take reciprocal of above equation and equate to two;
=


-3x=4x-6


-x-6x+6=0
x(x-1)-6(x-1)=0
(x-6)(x-1)=0
Take the bracket x-6=0 so that Carl works positive hours
x-6=0
x=6
This type of parabola opens either to the left or to the right. The negative makes it open to the left.
Answer:
30/100 *200/1= 6000/100=60