**Interest**

**1 . A man deposits TK.1000 in a bank at 8% interest rate compounded annually. At the end of the 3rd year, ehat will be the total amount including interest ?**

Solution :

we know, c= p.(1+r)^n

=1000×(1+0.08)^3= 1259.712

**2. If TK.1000 is invested in a account paying 10% compounded annually, how much would be the nearest ending balance at the end of 3 years?**

Solution:

C=p×(1+10/100)^3=1331.

**3. A person wishes to accumulate Tk. 500000 by the end of 15 years by making equal half-yearly deposits over the next 15 years. If he earns 10% on the investment, how much must he deposit at the end of each half-year?**

Solution :

FV=A×{(1+i)^n-1}/i

>500000=A×{(1+0.05)^30-1}/.05

>A=500000/66.44

>A=7525.59

**4. How much interest will Tk. 10000 earns in 9 months at an annual rate of 6%.**

Solution:

The interest in 12 months is

tk. 10000 × 6/100

=tk. 600

So , interest in 1 month is tk. 600/12.=tk. 50

And interest in 9 months is tk. 90×50 =tk. 450

**5. What annual rate was paid if Tk. 50000 earned Tk. 3000 in interest in two years?**

Solution:

Solution : In 2 year tk. 50000 earned in tk. 3000 So In 1 year tk 100 earned in tk. 3000×100/ (5000×2)=tk. 3.

**6. A sum of money at simple interest amounts to Rs. 815 in 3 years and to Rs. 854 in 4 years. The sum is:**

Explanation:

S.I. for 1 year = Rs. (854 – 815) = Rs. 39.

S.I. for 3 years = Rs.(39 x 3) = Rs. 117.

Principal = Rs. (815 – 117) = Rs. 698.

**7. A man took loan from a bank at the rate of 12% p.a. simple interest. After 3 years he had to pay Rs. 5400 interest only for the period. The principal amount borrowed by him was:**

Explanation:

Principal = Rs. (100 x 5400 ) /12 x 3= Rs. 15000.

**8. How much time will it take for an amount of Rs. 450 to yield Rs. 81 as interest at 4.5% per annum of simple interest?**

Explanation:

Time = (100 x 81 years)/450 x 4.5 = 4 years.

**9. A sum of Rs. 12,500 amounts to Rs. 15,500 in 4 years at the rate of simple interest. What is the rate of interest?**

Explanation:

S.I. = Rs. (15500 – 12500) = Rs. 3000.

Rate = (100 x 3000 %)12500 x 4 = 6%

**10. A certain amount earns simple interest of Rs. 1750 after 7 years. Had the interest been 2% more, how much more interest would it have earned?**

Explanation:

We need to know the S.I., principal and time to find the rate. Since the principal is not given, so data is inadequate.