Haryana Police Constable Model Paper 9

Ravana does the work in $20$ days
Rama does the work in $16$ days
1 day work of Ravana $=\left(\frac{1}{20}\right)$
1 day work of Rama $=\left(\frac{1}{16}\right)$
∴ Total 1 day work of Ravana and Rama $=\left(\frac{1}{20}\right)+\left(\frac{1}{16}\right)=\left(\frac{27}{80}\right)=\frac{9}{80}$
Total 3 days work $=3\times \left(\frac{9}{80}\right)=\frac{27}{80}$
∴ remaining part of the work $=1-\left(\frac{27}{80}\right)=\frac{53}{80}$