Forfeiture amount per share is the amount to be received by the company on forfeiture of each share.
$$Forfeiture\quad Amount=Application\quad Amount\quad +\quad Allotment\quad Amount$$
Substitute the values in above equation
$$Forfeiture\quad Amount=Rs20 +Rs30= Rs50$$
Forfeiture amount is the money received by company on forfeiture (cancellation of share) or on the reissue of share.
$$Forfeiture\quad Amount= No.\quad of\quad shares \times Forfeiture\quad Amount$$
Substitute the values in the above equation
$$Forfeiture\quad Amount=50 \times50= Rs2500$$
$$Forfeiture\quad Amount\quad for\quad 20\quad shares= 200\times 50= Rs1000$$
$$Forfeiture\quad Amount\quad for\quad reissued\quad shares=20\times 10= Rs200$$
Profit on the reissue is the profit earned by the company when the forfeited shares are reissued
$$Profit\quad on\quad reissue=Forfeited\quad Amount\quad on\quad forfeiture- Forfeited\quad amount\quad on\quad reissue$$
Substitute the values in the above equation
$$Profit\quad on\quad reissue=Rs 1000- Rs 200= Rs 800$$
Hence, the profit earned on the reissue of shares is Rs $$800$$.
Share Forfeiture a/c Dr Rs800
To capital reserve a/c Rs800.