M4maths Previous Puzzles

18 Apr 2019 Simple Interest

Divide Rs. 21411 into 3 parts so that their amount after 2,3 and 4 years respectively may be equal, the rate of interest being 5% per annum at simple interest. The second part is

OPtion

1) 8197
2) 6831
3) 7452
4) 7128
5) 6830
6) 7450
7) 7132
8) 6833
9) 7130
10) None of these

Solution

Let the parts be x, y and z
x + (x * 2 * 5/100) = y + (y * 3 * 5/100) = z + (z * 4 * 5/100)
11x/10 = 23y/20 = 6z/5 = k
x = 10k/11, y = 20k/23, z = 5k/6
But x + y + z = 21411
10k/11 + 20k/23 + 5k/6 = 21411
k = 8197.2
y= (20/23)*8197.2 = 7128
Option 4)

Correct Option: 4 Best Solution (2)