Guest lectures on five subjects viz., Economics, History, Statistics, English and Mathematics have to be arranged in a week from Monday to Friday. Only one lecture can be arranged on each day. Economics cannot be scheduled on Tuesday. Guest faculty for History is available only on Tuesday. Mathematics lecture has to be scheduled immediately after the day of Economics lecture. English lecture has to be scheduled immediately before the day of Economics lecture.
Which lecture is scheduled on Monday?

EXPLANATION

The schedule for the guest lectures can be determined by systematically applying the given constraints:

Guest faculty for History is available only on Tuesday. Therefore, History is scheduled on Tuesday.
English lecture has to be scheduled immediately before the day of Economics lecture.
Mathematics lecture has to be scheduled immediately after the day of Economics lecture.

These three lectures form a consecutive block: English - Economics - Mathematics.

Economics cannot be scheduled on Tuesday. Since History is on Tuesday, the English - Economics - Mathematics block cannot start on Monday (as Economics would then be on Tuesday).
If English is on Wednesday, then Economics is on Thursday, and Mathematics is on Friday. This sequence fits the remaining days.

Combining these deductions, the partial schedule is:

The only remaining subject is Statistics, and the only remaining day is Monday. Therefore, Statistics must be scheduled on Monday.

Statistics

Based on the derived schedule, Statistics is the lecture scheduled on Monday.

History:

History is explicitly stated to be scheduled on Tuesday, as the guest faculty is available only on that day.
Economics:

Economics cannot be scheduled on Tuesday, and due to the sequence English - Economics - Mathematics, Economics is scheduled on Thursday.
Mathematics:

Mathematics is scheduled immediately after Economics. Since Economics is on Thursday, Mathematics is scheduled on Friday.