Unit-14 Commercial Mathematics

In this unit you will learn about profit and loss, various taxes, shares and debentures.

ind the missing quantity against each of the following:
i) P = Rs.4500, t = 4 years, A = Rs.6000 , r = ?
ii) I = Rs.800, r = 0.08, P = Rs.1000, t = ?
iii) P = Rs. 8000, t = 8 years, r = 6%, A = ?
iv) A = 2P, t = 6 years, r =?

Answer

i) A = P(1 + rt)

6000 = 4500(1 + r × 4)

4/3 = 1 + 4r or r = 1/12 = 0.0633 = (0.0633 × 100)% = 6.33%

ii) I = Prt

800 = 1000 × 0.08 × t

t = 10 years.

iii) A = P(1 + rt) = Rs.8000(1 + 0.06 × 8) = Rs.8000 × 1.48 = Rs.13440

iv) A = P(1 + rt)

2P = P(1 + r × 6)

r = 1/6 = 100/6% = 16(2/3)%