Question

How many days will it take for a sum of $4,000 to earn $80 interest if it is deposited in a bank paying ordinary simple interest at the rate of 5%/year?

Answer 1

It will take 146 days to earn an interest of $80.

Explanation:

The simple interest formula is:

`I=(P* r* t)/(100)`

It is provided that:

I = $80

P = $4,000

r = 5% p.a.

Compute the time required as follows:

`I=(P* r* t)/(100)`

`t=(I* 100)/(P* r)`

`=(80* 100)/(4000* 5)\\\\=0.4\ \years\\\\=0.4* 365\ days\\\\=146\ days`

Thus, it will take 146 days to earn an interest of $80.