A sum of ₹3125 amounts to 3515.20 in 3 years at x% p.a., interest being compounded yearly. What will be the simple interest (in ₹) on the same sum and for the same time at (x + 2)% p.a.?
Answer & explanation
Correct answer: option 1
Amount = Principal × ( 1 + \(\frac{rate }{100}\) )t
3515.20 = 3125 × ( 1 + \(\frac{x }{100}\) )³
3515.20 = 3125 × ( \(\frac{100+x }{100}\) )³
\(\frac{3515.20 }{3125}\) = ( \(\frac{100+x }{100}\) )³
\(\frac{26 }{25}\) = ( \(\frac{100+x }{100}\) )
2500 + 25x = 2600
25x = 100
x = \(\frac{100 }{25}\) = 4%
New rate = ( x + 2 )% = ( 4 +2 )% = 6%
Simple interest = \(\frac{P×R×T}{100}\)
= \(\frac{3125×6×3}{100}\)
= 562.50