At a museum, ticket prices are $13 for adults and $11 for children. If a tour group paid $179 for their tickets, how many people were in the tour group?
I'm not Ms. Sue but I could try to help. Let's create a formula:
Let A denote the # of adult tickets
Let C denote the # of child tickets
Therefore...
$13 x A + $11 x C = $179
13A + 11C = 179
So from this point forward, I would ask the following. What # must you subtract from $179 in order for it be divisible by 11. That number must also be a factor of 13.
Essentially what I'm saying is 11C = 179-13A
The answer to that would be the following:
13 x 7 = 91
179- 91 = 88
88/11 - 8
Therefore, 7 adults and 8 kids.
PS - You could do it the other way around where you could try to find the number divisible by 179 which is also a factor of 11 but I thought it would be easier to do it the other way around since we're more familiar with our 11 times tables.