Crashing Help?

[johnsmith123]

hi

I need help with Questions 4 and 5, I have my answer but it is different to the suggested solutions, so please tell me what you get becuase I think my answer is correct. Thanks

[plato]

My answers are:
4(a) Activity E starts at the end of B and joins to the end of C. Then activity F starts at the ends of C&E and joins at the end of Activity D
4(b) LST for C is 6. EST for F is 12.
4(c)  ABEFG
4(d) 15

5(a) Crash B by 3 and E by 1 which reduces ABEFG to 11. But this makes a new critical path ACFG of length 12. So then crash C by 1 to give the shortest possible time along two critical paths of ABEFG and ACFG, both 11 long.
5(b) 3 week saving costs $12000 by crashing E by 1 and B by 2.
       4 week saving costs $21000 by crashing E by 1, B by 3 and C by 1 as explained in answer to 5(a)