A lent Rs. 5000 to B for 2 years and Rs 3000 to C for 4 years on simple interest at the same rate of interest and received Rs 2200 in all from both of them as interest. The rate of interest per annum is

Answer: Option A

Explanation:

S.I. = 956 - 800 = Rs 156

\begin{aligned}
R = \frac{156*100}{800*3} \\
R = 6\frac{1}{2}\% \\

\text{ New Rate = }6\frac{1}{2}+4 \\
= \frac{21}{2} \% \\

\text{ New S.I. = }800\times\frac{21}{2}\times{3}{100} \\
= 252
\end{aligned}

Now amount will be 800 + 252 = 1052

Answer: Option A

Explanation:

Let the sum is 100.

As financier includes interest every six months., then we will calculate SI for 6 months, then again for six months as below:

SI for first Six Months = (100*10*1)/(100*2) = Rs. 5

Important: now sum will become 100+5 = 105

SI for last Six Months = (105*10*1)/(100*2) = Rs. 5.25

So amount at the end of year will be (100+5+5.25)
= 110.25

Effective rate = 110.25 - 100 = 10.25

Answer: Option D

Explanation:

Let the principal be P and rate be R

then

\begin{aligned}
\text{ratio = } [\frac{(\frac{P*R*6}{100})}{(\frac{P*R*9}{100})}] \\

= \frac{6PR}{9PR} = 2:3
\end{aligned}

Answer: Option C

Explanation:

SI for 3 year = 2600-2240 = 360
SI for 2 year 360/3 * 2 = 240
principal = 2240 - 240 = 2000

Answer: Option D

Explanation:

We need to calculate the profit of B.
It will be,
SI on the rate B lends - SI on the rate B gets

\begin{aligned}
\text{Gain of B}\\ &= \frac{3500\times11.5\times3}{100} - \frac{3500\times10\times3}{100}\\
= 157.50
\end{aligned}