Given:
A group of students is on a sightseeing tour. The total fare is $120 and this is to be shared equally among the students. If two more students join the tour, each will pay $2 less.
Objective:
To obtain the original number of students in the group.
Step-by-step explanation:
Let x = the original number of students
Trip cost, 120 dollars.
Each Student's price

If x+2 students, then 2 dollars per student is less. therefore we can write:

The left part is the price if two more students, and the right part is the original student price minus $2.
They are equal.
Further, the solution is as follows:

Further the solution is as follows:

As x denotes the number of students in the group it cannot be negative.
Therefore the value of x is 10.
Final Answer:
The original number of students in the group is 10.