Why are dishonored cheques added in this question?

Dear student Here we have to reach at balance as per cash book from that of pass book. When the cheques will be dishonored intimation for the same will be available with the bank and bank will already record the same by deducting. But in the cash book same will not be recorded. So the same will be added back to the pass book by crediting it in order to reach at the balance of cash book. Regards