Correct Answer - a
(a) Time = 3 years, Rate = 5%
Difference between CI & SI =Rs. 15.25
Effective Rate % CI in 3 years = 15.7625%
Effective Rate % SI in 3 years = 5`xx`3=15%
According to the question,
(15.7625-15)% of sum
=Rs. 15.25
Sum= `(15.25)/(0.7625)xx100` = Rs. 2000
Alternate
Rate% = 5% = `(1)/(20)`
Let total principal = `(20)^(3)` = 8000 units
According to the question,
61 units = Rs. 15.25
8000 units= `(15.25xx8000)/(61)`
= Rs. 2000
Henced Required sum = Rs. 2000