Answer:
405 tickets
Explanation:
Let's say Emma is x. Since Lily sold 4 times as much as Emma, Lily is 4x (in terms of x). Since Lily sold 150 concert tickets more than Emma, we can relate that 4x is also equal to 150 + x
The equation becomes 4x = x + 150; and simplified to 3x = 150; x = 50.
Since both Lily and Mar sold 355 tickets and you have the number of tickets that Lily sold, you can do 355 - 200 and get 155 tickets that Mar sold.
So then the final equation is 200 + 50 + 155 which equals 405.