The precedence relationship and the task-times for an assembly line are given below:

Task Immediate Predecessor Time,

(min.)

a– 3 ba 4 c– 7 dc 4 ed 7 f e 10 ge 7 h– 2 i b,f 9 jh 9 ki 7 lg 8 mj 4 n m, k 10 ol 6 pk 2 qo 8 rp 5 s q, n 3 tr 7 us 4 v t, u 3 wv 9 xw 1 (i) Balance the line for a production rate of 4 units per hour.
(ii) What number of work stations are required if the line is to be balanced for a production rate of 3 units per hour?