Question

एक महाजन 9 रुपया इस शर्त पर देता है की 1 रुपया प्रतिमाह की दर से 10 माह मे वापस करना है। ब्याज की दर प्रतिवर्ष क्या है?

Answer 1

SI=PRT/100 ,SO HERE here P=9,rate is 1 p.m,t=10 months. Rate %=11.11%.
So si=9×10×11.11/100=9.99which is equal to 10 rupees,so si =10 rupee

Answer 2

Principal = Rs 9,

Simple Interest= Rs 1  per month for ten months

Amount = 1 × 10 = Rs 10

Simple interest = Amount - Principal

                          = 10 - 9

                           = Rs 1

Time = 10 months = $\frac{10}{12}= \frac{5}{6}$ years

Let Rate of interest = R %

Formula for simple Interest

→Simple interest = $\frac{\text{Principal}\times\text{Rate of interest}\times Time}{100}$

→1 = $\frac{9\times R\times\frac{5}{6}} {100}$

→ 1 =$\frac{3 \times3\times R\times\frac{5}{3\times 2}} {5\times20}$

→ $1 = \frac{3R}{40}$

→ R = $\frac{40}{3}$% = 13 $\frac{1}{3}$%