Answer: 3/2
Step-by-step explanation:

2 * 7 = 14 (the number of tiles for each row) 23 - 14 = 9 (the number of tiles subtracted from how many tiles that are taken away) 9 tiles are in the seventh row.
6/10 + 7/12 = 142/120 = 71/60 = 1.18 (One whole number, and 11/60)
A) 6 because 12 divided by 2 is 6
B) 9 because 45 divided by 5 is 9
C) 23 because 207 divided by 9 is 23