Simple Interest Practice Test 4

Let the sum of money lent at 10% = x
Let the sum of money lent at 15% = y
So, his income = Rs 1,900
$\frac{10}{100}\mathit{x}+\frac{15}{100}\mathit{y}=1900$
$10\mathit{x}+15\mathit{y}=190000$ ......(i)
If the rate of interest is interchanged, then he earns Rs 200 more. So,
$\frac{15}{100}\mathit{x}+\frac{10}{100}\mathit{y}=2100$
$15\mathit{x}+10\mathit{y}=210000$ ......(ii)
Now solving equation (i) and (ii) we get,
y = 6,000Substituting the value of y in equation (i)
$10\mathit{x}+\left(15\times 6,000\right)=1,90,000$
$10\mathit{x}=1,90,000-9,000$
$\mathit{x}=10,000$
So, the total sum of money $=\mathit{x}+\mathit{y}=10,000+6,000$ = Rs 16,000
Rate of interest = 15%
$\mathit{S}\mathit{I}=\frac{16000\times 15\times 1}{100}=2400$
So, the amount is Rs 2,400.