Question

find how long it will take for an investment sum of $40000 to generate simple interest of $8000 at 5% per annum​

Answer 1

It will take 4 years

Explanation:

The formula of the simple interest is I = Prt, where

• P is the investment

• r is the annual rate in decimal

• t is the time

∵ The investment is $40000

∴ P = 40000

∵ The simple interest is $8000

∴ I = 8000

∵ The rate of interest is 5%

∴ r = 5%

→ Change it to decimal by divide it by 100

∴ r = 5 ÷ 100 = 0.05

→ Substitute them in the formula above

∵ 8000 = 40000 × 0.05 × t

∴ 8000 = 2000t

→ Divide both sides by 2000

∴ 4 = t

∵ t is the time of investment

∴ It will take 4 years