John invested a sum of money at an annual simple interest arte of 10%. At the end of four years the amont invested plys interest earned was 770. The amount =invested was:(जॉन ने एक धनराशि को 10 % वार्षिक साधारण बियाज की दर से निवेशित किया। चार वर्षो बाद राशि, बियाज सहित रुपया 770 हो जाता है तदनुसार वह कितने थी )

Options

A. 650
B. 3.5
C. 550
D. 500

Explanation

(c ) Let the amount invested(माना की निवेश की शेष राशि) =Rs P
Accordingt to the question, `P+(Pxx10xx4)/(100)=770`
`P+(4P)/(10)=770`
`(14P)/(10)=770 Rightarrow P =(770xx10)/(14)=550`
Hence Required invested amount(तक)=550
Alterante (वैकल्पिक विधि )
`10%=(1to "Interest")/(10to"Principal")`
Interest in 4 years=`1xx4=4`
`"Amount"=("interest"+"principal")=4+10=14`
According to the question,
14units=770
`1 "units"=(770)/(14)xx10=550`
The amount invested =550