Aptitude Day 194

Problems on Simple Interest:

1. A sum of money at simple interest amounts to 1000 in 2 years and to 1080 in 3 years. The sum is:

Solution:

                 S.I for 1 year = 1080-1000 = 80.

    

                 S.I for 2 years = 2*80 = 160.

                 Sum = 1000-160 = 840.

2. A sum of money amounts to 5000 after 3 years and 8000 after 8 years at the same rate of simple interest. The rate of interest per annum is:

Solution:

                  S.I per annum = (8000-5000)/5 = 600.

                  S.I for 8 years = 600*8 = 4800.

                  Principal = 8000- 4800 = 3200.

                 Rate = (100*4800)/(3200*8)

                          = 18.75%.