Duck eggs                     Chix eggs

Original                          (2/5) x 600 =240            600-240=360–> 3/5

Chix eggs broke                    0                                      ?

Final                                     240                                    ?

New units                             8u                                    7u

8u —> 240

u—>30

7u–>30 x 7 = 210

Hence broken chicken eggs = 360-210 = 150

Total eggs are 600

Number of duck eggs = 2/5 * 600 = 240

After some chicken eggs were broken, total number of eggs decreased and given now number of duck eggs become 8/15 of  total eggs,

Total number of eggs after delivery = 240 * 15/8 -= 450

So total number of chicken eggs broken = 600-450 = 150