I found the following problem in a book and don't understand exactly what is being asked.
(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 ?
The answer given in my book is as follows:
One brother is available at a particular time on all seven days of the week.