Respuesta :
5.90% much was the interest rate .
Step-by-step explanation:
Here we have , If Martin deposited \$211 into an account and earned $750 of interest over 5 years, We need to find how much was the interest rate . Let's find out:
Let us suppose that interest rate was x% per month! So , Amount of money he earned as interest per month :
⇒ [tex]\frac{211(x)}{100}[/tex]
Now , For one year( 12 months ) he earned :
⇒ [tex]\frac{211(x)}{100}(12)[/tex]
∴For five year he earned :
⇒ [tex]\frac{211(x)}{100}(12)(5)[/tex]
According to question , he earned $750 of interest over 5 years i.e.
⇒ [tex]\frac{211(x)}{100}(12)(5) =750[/tex]
⇒ [tex]\frac{211(x)}{100}(60) =750[/tex]
⇒ [tex]x =\frac{750(100)}{211(60}[/tex]
⇒ [tex]x =5.90\%[/tex]
Therefore , 5.90% much was the interest rate .
The interest rate is 7.1%
Step-by-step explanation:
It is given that,
- The amount Martin deposited into the account, P = $2,110
- The interest he earned, I = $750
- The time period, t = 5 years.
To find the interest rate :
The formula used here is given by,
Interest = P× r× t
where,
- P is the principal amount deposited in the account.
- t is the time period
- r is the interest rate
Now, substituting P= $211 , t= 5 and I = $750
⇒ 750 = 2110 × 5 × r
⇒ 750 = (10550×r)
⇒ 750 ÷ 10550 = r
⇒ r = 0.071
The rate should be represented in the percentage, therefore, multiply it by 100.
Interest rate = 0.071 × 100
Rate = 7.1 %
∴ The interest rate is 7.1%