'practical' or 'practically'?
Given a tight schedule of schoolwork, the child learns to prepare his own schedules of work and play; the more practical and less serious ones manage to take time out of their busy schedules of assignments, reports and tests and examinations to go with their friends on relaxation entertainment.

Why using ' the more practical and less serious ' here instead of using ' the more practically and less seriously ' ?
I assume it should be used to modify the verb 'manage', am I right?

Question

'practical' or 'practically'?
Given a tight schedule of schoolwork, the child learns to prepare his own schedules of work and play; the more practical and less serious ones manage to take time out of their busy schedules of assignments, reports and tests and examinations to go with their friends on relaxation entertainment.

Why using ' the more practical and less serious ' here instead of using ' the more practically and less seriously ' ? 
I assume it should be used to modify the verb 'manage', am I right?

Answer

Practical and serious are adjectives describing "ones" which refers to a group of the children.

Practically and seriously are adverbs that would modify a verb.  Practical and serious are adjective which describe nouns.

The sentence could be rewritten "The more practical and less serious children manage to take time out......"

Hope that helps!

Answer

I think they are describing the children themselves not their action(manage).