A man earns $112 interest in one year on an investment of $1,400. What was his rate of interest?

Question

ranga · Answer

Interest = P * r * t  = $112
where P is the principal = $1,400
r is the rate of interest per year in decimal.
t is the number of years invested = 1 year

Substitute the numbers in (1) and solve for r.

Multiply by 100 to convert decimal to percentage.

ranga · Answer

The first line is equation (1)

anonymous · Answer

look i dont even know how to multiply very good let alone all of this...

ranga · Answer

Interest = P * r * t = 112
Put P = 1400, t = 1 in the above equation:
1400 * r * 1 = 112
divide both sides by 1400
r = 112/1400 = 0.08
Multiply 0.08 by 100 to convert it to percentage.
r = 0.08 * 100 = 8%