Given:
The principal amount is P = $3000.
The rate of interest is r = 5% = 0.05.
The interest rate is A = $600.
The objective is,
a) To find the number of years.
b) To find the monthly payment.
Step-by-step explanation:
a)
The general formula for simple interest is,
![A=P* n* r\text{ . . . . . .(1)}](https://img.qammunity.org/2023/formulas/mathematics/college/ec5bv6vakzofkvwr5orzq0la9wbe83hzim.png)
To find n:
On plugging the given values in equation (1),
![\begin{gathered} 600=3000* n*0.05 \\ n=(600)/(3000*0.05) \\ n=4 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/x72qejpfoeci5h562cof7smlxky2grwvs2.png)
b)
Since, the total amount of the item can be calculated as,
![T=A+P\text{ .. . . . (2)}](https://img.qammunity.org/2023/formulas/mathematics/college/3179rpn1wgs3jcdns8w4cjri5q95v56zp1.png)
On plugging the obtained values in equation (2),
![\begin{gathered} T=600+3000 \\ T=3600 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/vgjjf7c5epg2s4lswtux25bgiiyc7vminw.png)
To find monthly payment:
Now, the monthly payment can be calculated as,
![m=(T)/(n*12)\text{ . . . . .(3)}](https://img.qammunity.org/2023/formulas/mathematics/college/n248f6dmiw8qnzv7ic7lxm3f9fuerz6qot.png)
Here, m represents the monthly payment, the product of 12 is used to convert the number of years into the number of months.
On plugging the obtained values in equation (3),
![\begin{gathered} m=(3600)/(4*12) \\ m=75 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/xnjc85ml5gpezwjwyguzmi30x58klu2wni.png)
Hence,
a) The number of years is 4 years.
b) The monthly payment is $75.