Final answer:
By creating a system of equations based on the provided revenue and pricing information for the whale-watching tour group, and solving these equations, it was determined that there were 12 children in the group.
Step-by-step explanation:
To determine how many people in the group were children on the whale-watching tour, we can set up a system of equations based on the given information. The company takes groups of 21 people and charges Rs. 80 per adult and Rs. 60 per child. The total revenue for one group is Rs. 1440.
Let A represent the number of adults, and C represent the number of children. Then, we have two equations:
- A + C = 21 (since the group consists of 21 people).
- 80A + 60C = 1440 (representing the total revenue).
We can solve these equations simultaneously. First, let's isolate one of the variables in the first equation:
A = 21 - C
Now, substitute this into the second equation:
80(21 - C) + 60C = 1440
1680 - 80C + 60C = 1440
-20C = -240
C = 12
So, there were 12 children in the group.