Answer:
there are 15 long tables and 0 round tables
Explanation:
You can set up two equations to represent the number of people seated at each type of table. Let x be the number of long tables and y be the number of round tables. The first equation is: 12x + 8y = 156. This equation represents the total number of people seated, with 12 people seated at each long table and 8 people seated at each round table.
The second equation represents the total number of tables: x + y = 15.
You can solve this system of equations using substitution. First, solve for x in the second equation by subtracting y from both sides: x = 15 - y. Substitute this expression for x into the first equation: 12(15 - y) + 8y = 156.
This simplifies to: 180 - 12y + 8y = 156.
Combining like terms, we get: -4y = 24.
Dividing both sides by -4, we get: y = -6.
Since y represents the number of tables, and we can't have negative tables, this solution is not valid. Therefore, there are no round tables.
Substituting y = 0 into the equation x + y = 15, we get: x + 0 = 15. Solving for x, we find that there are 15 long tables.
Therefore, there are 15 long tables and 0 round tables.