Six lectures are scheduled in a week starting from Monday and ending on Sunday with one off day in between. Computer science is not on Tuesday or Saturday. Psychology is immediately after organisational behaviour. Statistics is not on Friday and there is one day gap between statistics and Research methods. One day prior to the schedule of Economics there is no lecture (as that day is the off day and Monday is not the off day).
On which day is computer science scheduled?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Thursday
Seven days hold six lectures and one off day. The off day is not Monday, and Economics comes the day after it, so the off day cannot be Sunday either. The quickest way is to try each possible off day and test the other clues (“one day gap” means one day between Statistics and Research methods).
Off day Tuesday to Friday (Economics on the next day) — each fails:
Tuesday (Economics Wednesday): the free days are Monday, Thursday to Sunday. Statistics and Research methods need Thursday-Saturday or Friday-Sunday, and then no two consecutive days are left for Organisational behaviour and Psychology.
Wednesday (Economics Thursday): the only pair with a day between is Friday-Sunday. Then Organisational behaviour and Psychology take Monday-Tuesday and Computer science gets Saturday, which is not allowed; no other placing works.
Thursday (Economics Friday): Statistics and Research methods must take Monday and Wednesday, and the consecutive pair then takes Saturday-Sunday, leaving Tuesday for Computer science, which is not allowed.
Friday (Economics Saturday): whichever two consecutive days the pair takes among Monday to Thursday, the three days left (with Sunday) contain no two days with one day between them.
Off day Saturday (Economics Sunday), lectures Monday to Friday:
Statistics and Research methods with one day between: Monday-Wednesday, Tuesday-Thursday or Wednesday-Friday
Monday-Wednesday leaves Tuesday, Thursday, Friday: the pair takes Thursday-Friday and Computer science Tuesday, not allowed
Tuesday-Thursday leaves Monday, Wednesday, Friday: no two consecutive days for the pair
Wednesday-Friday: Statistics is not on Friday, so Statistics Wednesday, Research methods Friday
Monday, Tuesday and Thursday are left: Organisational behaviour Monday, Psychology Tuesday, and Computer science Thursday