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A person invests a sum of $6580 at an 8% per annum rate of interest to obtain a
total amount of $8685.6 including simple interest after a certain number of
years. For how many years did he invest the amount to obtain the total
amount?
5 years
4 years
6 years
3 years
A person invests a sum of $6580 at an 8% per annum rate of interest to obtain a
total amount of $8685.6 including simple interest after a certain number of
years. For how many years did he invest the amount to obtain the total
amount?
5 years
4 years
6 years
3 years
Answers & Comments
I = interest
P = sum invested
A = amount
T = time
R = rate of interest
We know,
I = (P×R×T)÷100
Therefore,
I = (6580×8×T)÷100
= 526.4×T -----------------------(i)
According to question,
A = 8685.6
I = A - P
= 8685.6 - 6580
=2105.6 -----------------------(ii)
From equation (i) and (ii) we get,
526.4×T = 2105.6
T = 4
Hence, 4 years.