Question

the simple interest of a certain sum for 8 months at 4% is rupees 129 less than the simple interest on the same sum for 15 month at 5% per annum what is the sum ?​

Answer 1

Answer:

3600 rupees is the sum amount

explanation-

let sum amount be x

the time periods are 8/ 12 i.e 2/3 year and 15/12 i.e. 5/4 years

now

interest in case 1 = interest in case 2 - 129

PRT/100 = PRT/ 100 - 129

(x*4*2/3)/100 = (x*5*5/4)/100 - 129

8x/300= 25x/400- 129

25x/400 - 8x/300= 129

(75x- 32x)/1200= 129

43x= 129*1200

x= (129* 1200)/43

x= 3600 rupees

hope it is helpful