Question

A sum of money will treble itself in 15 year at simple interest with yearly rate of:
a) 13¹/3
b) 16²/3
c) 12²/3
d) 20​

Answer 1

Answer:

Let principal = P

Then, SI = 2P & Time = 15 years

? Required rate = (100 x SI) / (P x T) = (100 x 2P) / (P x 15) = 200/15 = 131/3 per annum

Answer 2

Step-by-step explanation:

Let principal be 100

Let principal be 100Interest rate p.a. I

Let principal be 100Interest rate p.a. I100 + 15.5 x I = 300

Let principal be 100Interest rate p.a. I100 + 15.5 x I = 300I = 200/15.5

Let principal be 100Interest rate p.a. I100 + 15.5 x I = 300I = 200/15.5Let The amount to be doubled in n years

Let principal be 100Interest rate p.a. I100 + 15.5 x I = 300I = 200/15.5Let The amount to be doubled in n years100 + n x I = 200

Let principal be 100Interest rate p.a. I100 + 15.5 x I = 300I = 200/15.5Let The amount to be doubled in n years100 + n x I = 200Or n x I = 100

Let principal be 100Interest rate p.a. I100 + 15.5 x I = 300I = 200/15.5Let The amount to be doubled in n years100 + n x I = 200Or n x I = 100Or n x 200/15.5 = 100

Let principal be 100Interest rate p.a. I100 + 15.5 x I = 300I = 200/15.5Let The amount to be doubled in n years100 + n x I = 200Or n x I = 100Or n x 200/15.5 = 100n = 15.5 / 2 = 7.25 or 7 years 3 months.