(I).   Kamal is available at home from 12 noon to 4 p.m. on Tuesday, Thursday and Sunday.
(II).  His younger brother Navin is available at home on Monday, Thursday, Friday and Sunday between 10 a.m. to 2 p.m.
(III). The eldest brother Rajiv is available between 9 a.m. to 12 noon on Monday, Wednesday and Thursday and 2 p.m. to 4 p.m. on Friday, Saturday and Sunday.

For how many days only one brother is available at a particular time in a week ?

A. One
B. Two
C. Three
D. Four
E. None of these
Answer: D . Four


We prepare a table as under :

  Mon Tue Wed Thu Fri Sat Sun
9 a.m. to 10 a.m. R   R R      
10 a.m. to 12 noon N, R   R

N, R

N   N
12 noon to 2 p.m. N K   K, N N   K, N
2 p.m. to 4 p.m.   K   K R R K, R

Clearly, One brother is available time on all seven days of the week.