Let the sum of money lent at 10% = x
Let the sum of money lent at 15% = y
So, his income = Rs 1,900
x+y=190010x+15y=190000 ......(i)
If the rate of interest is interchanged, then he earns Rs 200 more. So,
x+y=210015x+10y=210000 ......(ii)
Now solving equation (i) and (ii) we get,
y = 6,000Substituting the value of y in equation (i)
10x+(15×6,000)=1,90,000 10x=1,90,000−9,000x=10,000So, the total sum of money
=x+y=10,000+6,000 = Rs 16,000
Rate of interest = 15%
SI==2400So, the amount is Rs 2,400.