First find how many tickets she needs for the roller coaster: 5 tickets/ride * 7 rides = <<5*7=35>>35 tickets
Then find how many tickets she needs for the giant slide: 3 tickets/ride * 4 rides = <<3*4=12>>12 tickets
Then add the number of tickets she needs for each ride to find the total number of tickets she needs: 12 tickets + 35 tickets = <<12+35=47>>47 tickets
#### 47