Let x = number of people that were supposed to go to the trip, where x is greater than or equal to 0.
Let y = price per person initially with x people going on the trip.
xy = 4600
Solve for y.
y = 4600/x
(x - 10)(y + 230) = 4600
Replace y with the fraction 4600/x.
(x - 10)[(4600/x) + 230)] = 4600
What you need to do:
1. Solve (x - 10)[(4600/x) + 230)] = 4600 for x.
2. When you find x, subtract 10 from the value of x to find the number of people that went on the expedition.
You finish.