Question

Los martes, la primera clase es de diez a... there are three missing blanks and you must complete the sentence

Answer 1

Okay okay so it looks like it's saying that the first class is from 10 to some time. 

Los martes, la primera clase es de diez a once en punto.

On Tuesdays, the first class is from 10 to 11 o'clock.

you can fill in 11 with whatever hour it actually is.