Question

at what rate percent per annum will rupees 400 and interest of rupees 78 in 3 by 2 years​

Answer 1

✡13%☑

Step-by-step explanation:

Given ⤵

• Principal(P) = Rs.400
• Simple interest (S.I.) =Rs.78
• Time(T) = 3/2years.

To find⤵

• Rate of interest (R)

Solution⤵

⚫Using formula

$R = \frac{S. I. \times 100}{ PT} \\ = \frac{78 \times 100}{400 \times \frac{3}{2} } \\ = \frac{78 \times 2}{4 \times 3} \\ = \frac{78}{6} \\ = 13$

✅Hence the rate of interest is 13%.

Extra points⤵

$S. I. = \frac{ PTR}{100} \\ P = \frac{S. I. \times 100}{TR} \\ T = \frac{S. I. \times 100}{PR} \\ R = \frac{S. I. \times 100}{PT}$

Where S. I. = Simple interest, P= Principal, T=Time and R= Rate of interest

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Hope this is helpful to you!

Answer 2

Step-by-step explanation:

Solution;

• Principal= RS 400

• Simple interest= RS 78

• Time=3/2

• Rate =?

Now,

Rate= 100 × SI / P×T

= 100 ×78 / 400 × 3/2

= 78 / 4×3/2

= 13%