What is the formula to solve the below?

Chapter 5: A company is setting up an assembly line to produce 90 units per hour. The table below identifies the work elements, times, and immediate predecessors.

Work Element	Time (Sec.)	Immediate Predecessor(s)
A	35	---
B	20	A
C	30	B
D	23	C
E	28	D
F	15	B
G	17	F
H	15	F
I	12	G,H
J	23	E,I

1. What cycle time is required to satisfy the required output?
2. What is the theoretical minimum number of stations?
3. Use one of the heuristic decision rules described in Table 5.3 on page 194 to balance the assembly line so that it will produce 90 units per hour. Clearly state the decision rule you use, and the work elements assigned to each station.
4. What is the efficiency of the line you found in part c?

Decision Rule	Logic
Longest work element	Picking the candidate with the longest time to complete is an effort to fit in the most difficult elements first, leaving the ones with short times to fill out the station.
Shortest work element	This rule is the opposite of the longest work element rule because it gives preference in workstation assignments to those work elements that are quicker. It can be tried because no single rule guarantees the best solution. It might provide another solution for the planner to consider.
Most followers	When picking the next work element to assign to a station being created, choose the element that has the most followers (due to precedence requirements). In Figure 5.5, item C has three followers (F, G, and I) whereas item D has only one follower (H). This rule seeks to maintain flexibility so that good choices remain for creating the last few workstations at the end of the line.
Fewest followers	Picking the candidate with the fewest followers is the opposite of the most followers rule.