Hey there!
Each table in the can seat 10 students, divide 40 and 10 to see how many tables can seat 40 students . . .
x = the amount of tables needed
40 divided by 10 = 4
10 x 4 = 40
x = 4 <--------
To fit 40 students, 4 tables are needed.
Hope this helps you.
Have a great day!