Questions

Hospitality actually means, taking care of guests in the best possible way.

Organizing, providing services and looking care after guests is included in it.

It means friendly and generous treatment of guests. 

Hospitality industry includes all companies involved in providing services for guests. They provide more mental satisfaction than tangible objects.

Delhi has highestnumber of historical monuments

Cellular respiration is best associated with the organelle Mitochondrion.

In the given puzzle, the logic is

2 + 3 = 10 => (2 + 3) * 2 = 10

6 + 3 = 54 => (6 + 3) * 6 = 54

8 + 3 = 88 =>  (8 + 3) * 8 = 88

Similarly,

9 + 7  => (9 + 7) * 9 = 16 x 9 = 144.