A person closer his account in an investment scheme by withdrawing ₹ 10000. One year ago, he had withdraw ₹ 6000. Two years ago, he had withdrawn ₹ 5000. Three years ago, he had not withdrawn any money. How much money had he deposited approximately at the time of opening the account 4 yr ago, if the annual simple interest is 10%?

Suppose the person had deposited ₹ P at the time of opening the account .
∴ After one year he had P + (P x 10 x 1)/100 = ₹ 11P/10
After two years, he had
11P/10 + (11P/10 x 10 x 1)/100 = ₹ 121P/100 ...(i)
After withdrawn ₹ 5000 from ₹ 121P/100, the balance
= ₹ (121P - 500000)/100
After 3 yr, he had
(121P - 500000)/100 + [(121P - 500000)/100 x 10 x 1]/100
= 11(121P - 500000)/100 ... (ii)
After withdrawn ₹ 6000 from amount (ii) the balance
= (1331P/1000 - 11500)
∴ After 4 yr, he had ₹ (1331P - 5500000)/1000 + 10% of ₹ (1331P - 5500000)/1000
= ₹ (11/10) x (1331P/1000 - 11500) ... (iii)
After withdrawn ₹ 10000 from amount (iii) the balance =0
∴ 11/10(1331P/1000 - 11500) - 10000 = 0
⇒ P = ₹ 15470