Manoj deposited a sum of Rs 64000 in a post office for 3 years, compounded annually at $7 \frac{1}{2} \%$ per annum. What amount will he get on maturity?
Principal for the first year $=$ Rs. 64000
Interest for the first year $=$ Rs. $\left(\frac{64000 \times 15 \times 1}{100 \times 2}\right)=$ Rs. 4800
Now, amount at the end of the first year $=$ Rs. $(64000+4800)=$ Rs. 68800
Principal for the second year $=$ Rs. 68800
Interest for the second year $=$ Rs. $\left(\frac{68800 \times 15 \times 1}{100 \times 2}\right)=$ Rs. 5160
Now, amount at the end of the second year $=$ Rs. $(68800+5160)=$ Rs. 73960
Principal for the third year $=$ Rs. 73960
Interest for the third year $=$ Rs. $\left(\frac{73960 \times 15 \times 1}{100 \times 2}\right)=$ Rs. 5547
Now, amount at the end of the third year $=$ Rs. $(73960+5547)=$ Rs. 79507
$\therefore$ Manoj will get an amount of Rs. 79507 after 3 years.