Calculating ROE

Shubham (student) (73 Points)

06 October 2020  
While calculating ROE do we take denominator as opening shareholders fund or closing shareholders fund or their average.
The question says :
Earnings during the year 195
No dividends distributed
Balance sheet totals:
2020
Assets-1580
Liabilities - 600
Paid up capital - 745
Retained earnings - 235

2021
Assets-1920
Liabilities - 745
Paid up capital - 745
Retained earnings - 430


Please help