The cost to rent a vacation house for a week is 850$. How much will Renee, susan and Martha each pay to rent this house for a week

I assume they are splitting up the cost of $850 to rent the house.

Let x represent cost to rent one house for one week.

Since there's three people each renting a house for a week, you would have

3x = 850

x = 283.333

$283.34