Answer: 5.25 or 5.5 [see note]
Step-by-step explanation:
1/4 (15 – 6) +3 [I'm not clear what is meant by the " : 12," so I left it out.]
1/4 (9) +3
9/4 + 3
2.25 + 3 = 5.25
===
If it is supposed to read
1/4 (15 – 6) +3/12
Then it would be
5.25 + 0.25 = 5.5
