Instructions

At an Electronic Data Processing Unit, five out of the eight program sets P, Q, R, S, T, U, V and W are to be operated daily. On any one day, except for the first day of a month, only three of the program sets must be the ones that were operated on the previous day. The
program operating must also satisfy the following conditions:
(i) If program ‘P’ is to be operated on a day, ‘V’ cannot be operated on that day.
(ii) If ‘Q’ is to be operated on a day, ‘T’ must be one of the programs to be operated after ‘Q’.
(iii) If ‘R’ is to be operated on day, ‘V’ must be one of the programs to be operated after ‘R’.
(iv) The last program to be operated on any day must be either ‘S’ or ‘U’.

Question 86

# Which of the following is true of any day’s valid program set operation?

Solution

Following are the conditions:

1. The following can be the possibilities with respect to P and V: P/V/None

2. The following can be the possibilities with respect to T and Q: Q...T

3. The following can be the possibilities with respect to R and V: R...V

4. The last has to be S or U.

Now, we shall test each of the options.

Option 1: If we can find a combination with P at the third place, this option will be incorrect. A possible combination can be: QTPW(S/U). Since all conditions are met in this combination, we know this option is incorrect.

Option 2: If we can find a combination with Q at the third place, this option will be incorrect. A possible combination can be: PWQT(S/U). Since all conditions are met in this combination, we know this option is incorrect.

Option 3: If we can find a combination with R at the fourth place, this option will be incorrect. There cannot be any valid combination since V has to come after R, but the last element shall be S/U. Hence, this is a correct option.

Option 4: If we can find a combination with U at the fourth place, this option will be incorrect. A possible combination can be: PQTUS. Since all conditions are met in this combination, we know this option is incorrect.