HELP
An entry pass to a museum costs $12 for a child and $15 for an adult. A total of 300 entry passes were sold, and the total money collected is $4140. The number of $15 entry passes sold are

Let’s define our variables: x represents child passes and y represents adult passes.

Now, let’s make some equations with the provided information.

First, let’s deal with the money

12x+15y=4140

Next, the amount of passes

x+y=300

Then, take the second equation, and subtract y over.

x=300-y

Now, we can substitute the equation above in for x in the first equation

12x+15y=4140
12(300-y) +15y =4140

Distribute the 12

3600-12y+15y=4140

Combine like terms, then subtract 3600 over

3y=540

Divide by 3 on both sides

y=180

So, 180 $15 entry passes were sold