Question

SI=40, rate=3.5, time=7.5yrs find principal

Answer 1

we know that

$Principal = \frac{i}{rt} \times 100 \\ \frac{40}{3.5 \times 7.5} \times 100 \\ \frac{40}{35 \times 75} \times 100 \times 10 \times 10 \\ \frac{8}{7 \times 15} \times 20 \times 10 \times 10 \\ \frac{8}{7 \times 3} \times 4 \times 10 \times 10 \\ \frac{8}{21} \times 400 \\ \frac{3200}{21} \\ 152.380 (aprox)$

Answer 2

$\blue{\bold{\underline{\underline{Answer:}}}}$

$\green{\therefore{\text{Principal=152.38\:rupees}}}$

$\orange{\bold{\underline{\underline{Step-by-step\:explanation:}}}}$

$\green{ \underline \bold{Given : }} \\ : \implies \text{Time (t)= 7.5 \: years} \\ \\ : \implies \text{Simple \: interest(S.I) = 40} \\ \\ : \implies \text{Rate(r) =3.5\%} \\ \\ \red{ \underline \bold{To \: Find: }} \\ : \implies \text{Principal(p) = ?}$

• According to given question :

$\bold{As \: we \: know \: that } \\ \circ \: \text{Simple \: interest} = \frac{ \text{Principal }\times \text{ Rate} \times \text{Time}}{100} \\ \\ \bold{Putting \: given \: values} \\ : \implies S.I = \frac{p \times r \times t}{100} \\ \\ : \implies 40= \frac{p \times 3.5\times7.5 }{100} \\ \\ : \implies p = \frac{40 \times 100}{3.5 \times7.5 } \\ \\ \green{ : \implies \text{p =152.38\: rupees}} \\ \\ \green{ \therefore \text{principal = 152.38 \: rupees}} \\ \\ \bold{Basic \: formula\:related\:to\:C.I} \\ \circ \: A = p(1 + \frac{r}{100} )^{t}$