Question 1133464
Let x be the cost of 20 units, then 1 rupee is (100%-25%)= (75%) of x. 

Given that 1 rupee = 100paise: 

{{{75x/(100) = 100}}}
{{{x=100*100/75}}}

x=133.33 paise

The cost of 20 units should be 133.33 paise.