James invested $4,000 at 5% interest per year; how long will it take him to earn $200 in simple interest?

You have to apply simple interest formula, I = (P×R×T)/100 where I represent interest amount, P is principle, R is interest rate and T is number of years :

[tex]I = \frac{PRT}{100} [/tex]

[tex]200 = \frac{4000 \times 5 \times T}{100} [/tex]

[tex]20000 = 20000T[/tex]

[tex]T = 1[/tex]

Answer Link

SnowyKíng SnowyKíng · Answer 2 · 2020-12-24T10:12:34+01:00

Given :

Principal, P = $ 4,000
Rate, R = 5 %
Interest Amount, I = $ 200

To Find :

Time, T = ?

Solution :

We, know that :

[tex] \underline{\boxed{\sf Interest \: amount = \dfrac{Principal \times Rate \times Time}{100}}}[/tex]

[tex] \underline{\boxed{\sf I = \dfrac{P \times R \times T}{100}}}[/tex]

By putting values, we have

[tex] \sf : \implies 200 = \dfrac{4000 \times 5 \times T}{100}[/tex]

[tex] \sf : \implies 200 \times 100 = 20000 \times T[/tex]

[tex] \sf : \implies 20000 = 20000 \times T[/tex]

[tex] \sf : \implies \cancel{\dfrac{20000}{20000}} = T[/tex]

[tex] \sf : \implies 1 = T[/tex]

[tex] \underline{\boxed{\sf T = 1 \: year}}[/tex]

It takes 1 year for him to earn $ 200 in simple interest.