Question

The activities of W, X, Y and Z are the direct precursors of A. What is the earliest starting time for A, if the activities of earliest finishing times are 12, 15, 10 and 6?

• A. 6
• B. 10
• C. 15
• D. 12

Hint:

Remember these path routing rules for network diagrams: - Forward Pass (Earliest Times): Use the MAXIMUM value of preceding finish times when paths merge. - Backward Pass (Latest Times): Use the MINIMUM value of succeeding start times when paths split.

Answer 1

The Correct Option is C

An activity that depends on several other activities cannot start until every single one of those activities has actually finished, so its earliest start time is fixed by whichever predecessor finishes last, not by the ones that finish early. Here W, X, Y and Z finish at 12, 15, 10 and 6 respectively, and A must wait for all four, so it can only begin once the slowest of them, X at 15, is done. The earliest start time for A is therefore 15, which is option 3.