Question

Rs 14000 is invested at 4 % per annum simple interest . How long will it take for the amount to reach Rs 16240. (Plz answer step by step accourding to class 7 standard).

Answer 1

p=14000
r=4%
amt=16240
T=?
hence,SI=amt-p
SI=16240-14000=2240
T=(100*SI)/(p*r)
T=(100*2240)/(14000*4)
T=224000/56000
T=4
hence,T=4yrs

Answer 2

Q. Rs 14000 is invested at 4 % per annum simple interest . How long will it take for the amount to reach Rs 16240

Ans : 4 years

Solution :


Principal : Rs 14000
Interest per annum at 4% =
$4 \div 100 \times 14000 \\ = 560$

Now, we know the amount of interest within one year.

Again, Amount in two years = 560+560
= 1120
Amount in three years = 1120+560= 1680
And Amount in four years = 1680+560 = 2240


Now add up the Principal with the amount of interest within four years
$14000 + (560 \times 4) \: {which \: is \: 2240} \\ \\ \: \: 14000 \\ + 2240 \\ \\ = 16240$
In order to get 16240, we multiplied the amount of interest in one year with four (i.e., 560x4)

The required time period is 4 years.