Interest at the time of maturity

\[=\text{ }Rs.\text{ }1200\]

Period (x)

\[~=\text{ }2\text{ }years\]

\[=\text{ }24\text{ }months\]

Rate of interest

\[=\text{ }6%\text{ }p.a.\]

Consider Rs. P p.m. as the monthly deposit

Since,

Interest

\[=\text{ }P\text{ }\times \text{ }\left[ x\text{ }\left( x\text{ }+\text{ }1 \right) \right]/\text{ }\left( 2\text{ }\times \text{ }12 \right)\text{ }\times \text{ }r/100\]

Putting the value of x

\[1200\text{ }=\text{ }\left( P\text{ }\times \text{ }24\text{ }\times \text{ }25 \right)/\text{ }24\text{ }\times \text{ }6/100\]

Or,

1200 = 6/4P

By cross multiplication

\[P\text{ }=\text{ }\left( 1200\text{ }\times \text{ }4 \right)/\text{ }6\]

\[=\text{ }800\]

Here monthly deposit

\[=\text{ }Rs.\text{ }800\]

So the amount of maturity

\[~=\text{ }P\text{ }\times \text{ }x\text{ }+\text{ }SI\]

\[=\text{ }800\text{ }\times \text{ }24\text{ }+\text{ }1200\]

\[=\text{ }19200\text{ }+\text{ }1200\]

\[=\text{ }Rs.\text{ }20400\]