Solution:

Dear this is not a GMAT level question. so please don't put these type of questions.

Explanation:

1200

1) after one yr interest paid 1200 * .05= 60 Rs and Principal paid 300 - 60=240

thus P remaining = 1200 - 240 = 960

2)after 2nd yr interest paid 960*.05= 48 Rs and Principal paid =300 -48 = 252 thus P remaining = 960 - 252 = 708

3)after 3rd yr interest paid 708 * .05 = 35.40 Rs and Principal paid 300 - 35.40 =264.60 thus P remaining = 708 - 264.60 = 443.40

4)after 4th yr interest paid 443.40 * .05= 22.17 Rs and Principal paid 300 -22.17 = 277.83 thus

P remaining = 443.40 - 277.83 = 165.57 Rs

thus this is the amt he has to paid after 4th yr.

If you want to calculate the 5th installment then

that is 165.57 * (1.05) = 173.8485 Rs