ANSWER
A) $200 less
EXPLANATION
To know how much more or less Isabelle or Carter will make if they merged with Carla's carwash, we have to find the difference between how much each of them makes now and how much they will make if they join forces with Carla.
Right now, Isabella and Carter make $6,000 a month. To find how much each of them makes, divide by 2 since they share the money 50/50 i.e. equally:
They make $3,000 each.
If they join forces with Carla, they will make $2,400 more per month. That is:
To find how much each of them will make, divide by 3 since they split it equally i.e. 33.3/33.3/33.3:
Now, we have to find the difference between the values:
As we can see, they will lose $200 per month if they join forces with Carla.
Hence, they will individually make $200 less if they merged with Carla's carwash.
The answer is option A.