Shandel went to the County Fair this summer and was surprised to see a math game on the midway among the games of skill and chance.
Picture of a Midway BarkerIn the game, the barker starts by thinking of a math rule or calculation. The player spins a number wheel to get her number, and the barker mentally applies his calculation to that number and quickly calls out the answer. They do this three times, with the barker writing down each pair of numbers for all to see.
The player spins one last time to get a fourth number. The barker then writes his answer down on a hidden board. To win the prize, the player has to correctly predict the number that the barker has written down.
Shandel gave it a try, and here are the results of her first three spins:
First = 3 to 1
Second = 15 to 25
Third = 7 to 9
On her fourth spin, Shandel got a 12 and was able to correctly predict the barker's answer and win the game.
What number did she predict?
All the rules are the same please help me!