A process flows through Steps A$-$D$.$

At Step A$,$ out of $100$ good units arriving, $100$ good units are sent to B including $10$ repaired units.

So $0$ units are scrapped at step A

i$.$e$.,$ Repair proportion $($RP$)$ at A $=10\%(10$ units repaired out of incoming $100$ units$)$

Step B $($Out of $100$ units recd from A$)90$ good units are sent to C including $6$ repaired units.

So $10$ units are scrapped at Step B$.$ RP at B $=6$ repaired $/100$ recd $=6\%$

Step C $($Out of $90$ good units recd from B$)87$ good units are sent to D including $15$ repaired units.

$3$ units are scrapped at C; RP $=15/90=16\mathrm{.}67\%$

Step D $($Out of $87$ good units recd from C$),85$ good units come out of D including $5$ repaired units.

$2$ units are scrapped at D; RP$=5/87=5\mathrm{.}75\%$