Washing machine loan

Thomas took out a loan to buy a washing machine. In the following 12 months, according to the contract, he had to repay the amount of 150 euros. The price of the washing machine is 1200 euros. What percentage is the annual interest rate? Write in the form % pa (pa = per annum).

Final Answer:

r =  50 %

Step-by-step explanation:

$$\begin{gathered} x=12\cdot 150=1800\text{Eur} \\ p=1200\text{Eur} \\ i=x-p=1800-1200=600\text{Eur} \\ r=100\cdot \frac{i}{p}=100\cdot \frac{600}{1200}=\frac{100\cdot 600}{1200}=\frac{60000}{1200}=50\% \end{gathered}$$

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