Answer:

Explanation:
Given


--- unknown
Required
Equation that can be used to find t
1 large table can take 15 people and there is only one large table.
So, we have:

1 small table can take 5 people and there are t small tables.
So, we have:

The room can accommodate 140 people.
So, we have:

This gives:

The above expression can be used to determine the number of small tables