Question

​A​ ​sum​ ​of​ ​Rs​ ​468.75​ ​was​ ​lent​ ​out​ ​at​ ​simple​ ​interest​ ​and​ ​at​ ​the​ ​end​ ​of​ ​1​ ​year​ ​and​ ​8​ ​months,​ ​the total​ ​amount​ ​of​ ​Rs​ ​500​ ​is​ ​recieved.​ ​find​ ​the​ ​rate​ ​of​ ​interest.

Answer 1

$sum \: of \: principa \: = 468.50 \\ time = 1year \: 8months = 1 \frac{8}{12} years = 1 \frac{2}{3} years = \frac{5}{3} years \\ amount \: = 500 \\ interest \: = 500 - 468.50 = 31.50 \\ rate \: of \: interest \: = \frac{31.50 \times 100}{468.50 \times \frac{5}{3} } = \frac{3150 \times 100 \times 3}{46850 \times 5} = 4.03\%$