Answer:
Seven Â
Step-by-step explanation:
Let G7, G8, and G9 be the numbers of students in the respective grades.
Then, G7 + G8 + G9 = LCM of G8 and G9
Data:
G8 = 5
G9 = 3
Calculations:
Multiples of 5: 1 2 Â Â Â Â Â 10 15
Multiples of 3: 1 Â 3 6 9 Â Â Â 15
The LCM of 5 and 3 is 15.
G7 + 5 + 3 = 15 Â Â Combine like terms
   G7 + 8 = 15   Subtract 8 from each side
      G7 = 7
There are seven students in Grade 7.