T.14 Critical path analysis questions for IB Business Management

Clínica Dental Arcos in Guadalajara, Mexico, must close while it is renovated, losing about MXN 40 000 of revenue a day. The tasks are shown in Table 1.

Table 1: Renovation tasks

Mavuno Builders Ltd is a construction company in Nairobi, Kenya. For small house extensions its site managers use Gantt charts. For a new six-storey school building, with more than 40 activities and a penalty clause for late completion, the operations director, Nyambura Kinyua, wants the managers to use critical path analysis (CPA) as well.

Distinguish between a Gantt chart and critical path analysis as planning tools for Mavuno Builders.

Dapur Rempah Sdn Bhd (DR)

DR runs a popular Malay restaurant in Kuala Lumpur, Malaysia. It has signed a lease for a second outlet in Petaling Jaya. Its founder, Aisyah Rahman, wants it open before Ramadan, which begins at the start of week 11 of the project. During Ramadan, buffets for the evening breaking of the fast (buka puasa) are DR’s busiest and most profitable trade: the new outlet is forecast to earn a contribution of RM150 000 in that month.

DR’s plan uses its own two carpenters and some casual workers for the fit-out, which would take 7 weeks and cost RM290 000 (Figure 1). A contractor has offered to complete the fit-out in 4 weeks for RM380 000. DR’s carpenters, who also maintain the first restaurant, built its much-praised wooden interior; the contractor’s work on other restaurants has received mixed reviews. Council permits for restaurants in Petaling Jaya have taken between 4 and 7 weeks this year.

The fit-out (D) starts when the layout design (B) is finished, and the kitchen (E) is installed after the fit-out. Task F can start only after the council permit (C) is granted. Task G needs tasks E and F to be finished.

Kibo Printers Ltd in Arusha, Tanzania, has won an order to print 20 000 school textbooks. The production manager, Juma Shirima, has drawn the network in Figure 1 (durations in days). The activities are: A approve artwork; B deliver paper; C make cover plates; D cut cover board; E print text pages; F print covers. The books are bound by another firm once E and F are complete.

Key: each node shows the node number (left), the earliest start time, EST (top right) and the latest finish time, LFT (bottom right). Arrows show activities with their durations.

Complete the network in Figure 1 by adding the missing earliest start times (EST) and latest finish times (LFT).

Tanjong Pay Pte Ltd is a fintech start-up in Singapore. It is developing a mobile payment app for hawker-centre stalls. Figure 1 shows the project network (durations in weeks). The activities are: A market research; B security planning; C design the app; D build the payment system; E build the user interface; F connect to banks; G prepare the marketing campaign; H beta testing with stallholders.

Key: each node shows the node number (left), the earliest start time, EST (top right) and the latest finish time, LFT (bottom right). Arrows show activities with their durations.

Riad Zitouna is a guest house in the old city of Fes, Morocco. It must close while it is renovated. The owner, Youssef Bennani, has been given the completed network in Figure 1 (durations in days). The activities are: A repair the roof; B strip old plaster; C rewire the rooms; D restore the courtyard fountain and tiles; E re-plaster the rooms; F furnish and clean.

Key: each node shows the node number (left), the earliest start time, EST (top right) and the latest finish time, LFT (bottom right). Arrows show activities with their durations.