6.) Simple interest on a sum of money for3 years at 8% is 180 less tha

1.	6.) Simple interest on a sum of money for3 years at 8% is 180 less than thesimple interest on the same sum for 4years at 12%. Find the sum
Answer» Principal + 8% p.a. interest on principal for n years = 180 …….. (1) Principal + 4% p.a. interest on principal for n years = 120 ……… (2) Subtracting equation (2) from equation (1), we get 4% p.a. interest on principal for n years = Rs.60. Now, we can substitute this value in equation (2), i.e Principal + 60 = 120 = Principal = Rs.60. We know that SI = , where p is the principal, n the number of years and r the rate percent of interest. In equation (2), p = Rs.60, r = 4% p.a. and the simple interest = Rs.60. Therefore, 60 =(60n4)/100 => n = 100/4 = 25 years.

6.) Simple interest on a sum of money for3 years at 8% is 180 less than thesimple interest on the same sum for 4years at 12%. Find the sum

Answer»

Principal + 8% p.a. interest on principal for n years = 180 …….. (1)

Principal + 4% p.a. interest on principal for n years = 120 ……… (2)

Subtracting equation (2) from equation (1), we get

4% p.a. interest on principal for n years = Rs.60.

Now, we can substitute this value in equation (2),

i.e Principal + 60 = 120

= Principal = Rs.60.

We know that SI = , where p is the principal, n the number of years and r the rate percent of interest.

In equation (2), p = Rs.60, r = 4% p.a. and the simple interest = Rs.60.

Therefore, 60 =(60*n*4)/100

=> n = 100/4 = 25 years.