**1.A sum of Rs. 1600 gives a simple interest of Rs. 252 in 2 years and 3 months. The rate of interest per annum is:?**

**2.A sum of Rs. 1750 is divided into two parts such that the interests on the first part at 8% simple interest per annum and that on the other part of 6% simple interest per annum are equal. The interest on each part (In rupees) is ?**

**3.Rs. 500 was invested at 12% per annum simple interest and a certain sum of money invested at 10% per annum simple interest at. If the sum of the interests on both the sums after 4 years is Rs. 480, the latter sum of money is?**

**4.A sum of money lent out at simple interest amounts of Rs. 720 after 2 years and to Rs. 1020 after a further period of 5 years. The sum is?**

**5.In what time will Rs. 72 become Rs. 81 at 25/4% per annum simple interest?**

**6.**

**The simple interest on a certain sum for 8 months at 4% per annum is Rs. 129 less than the simple interest on the same sum for 15 months at 5% per annum. The sum is:**

**7.A person deposited Rs. 400 for 2 years, Rs. 550 for 4 years and Rs. 1,200 for 6 years. He received the total simple interest of Rs. 1,020. The rate of interest per annum is ?**

**8.A sum of money becomes 7/6 of itself in 3 years at a certain rate of simple interest. The rate per annum is?**

**9.At what rate per cent per annum will the simple interest on a sum of money be 2/5 of the amount in 10 years?**

**10.Simple interest on a certain sum for 6 years is 9/25 of the sum. The rate of interest is ?**

**Answers:**

1.(c)

Principal, P = Rs. 1600

T = 2 year 3 months

= (2+3/12)yrs.=(2+1/4)yrs.= 9/4 yrs.

S.I = Rs. 252

R = % rate of interest per annum

R= (100×S.I.)/(P×t)

=(100×252)/(1600×9/4)

Rate of interest = 7% per annum.

2.(a)

Let first part = Rs. x and second part = Rs. (1750-x)

According to the question.

x×8/100=(1750-x)×6/100

8x + 6x = 1750 x 6

14x = 1750 x 6

x=(1750×6)/10=Rs.750

Interest = 8% of Rs. 750

= 750 × 8/100=Rs,750

= 750 × 8/100=Rs.60

3.(c)

Simple interest gained from Rs. 500

= (500×12×4)/100 = Rs. 240

Let the other Principal be Rs. x.

S.I. gained = Rs. (480 -240) = Rs. 240

(x×10×4)/100=240

x=(540×100)/40 = Rs. 600

4.(b)

Principal + SI for 2 years = Rs. 720 …..(i)

Principal + SI for 7 years = Rs. 1020 ….(ii)

Subtracting equation (i) from (ii) we get,

SI for 5 years

= Rs. (1020 -720) = Rs. 300

SI for 2 years = Rs. 300× 2/5= Rs. 120

Principal = Rs. 720- Rs. 120 = 600

5.(a)

Interest = Rs. (81-72) = Rs. 9

Let the time be t years.

9 = (72×25×t)/(4×100)

t=(9×400)/(72×25)=2 years

6.(d)

Let the sum be Rs. x

(x ×5 ×15)/(100 ×12)-(x ×4 ×8)/(100 ×12)=129

x/(100×12) (75-32)=129

x=(129×1200)/43= Rs. 3600

7.(a)

Let the rate of interest be R per cent per annum.

(400×2×R)/100+(550×4×R)/100+(1200×6×R)/100=1020

8R + 22R + 72R = 1020

102 R =1020

R = 1020/102=10%

8.(a)

Principal = P

Amount = 7p/6

S.I. = 7p/6-P=P/6

? R=(S.I×100)/(P×T)=(P×100)/(6×p×3)

= 50/9=5 5/9%

9.(a)

10.(a)

Rate = (SI ×100)/(Principal ×Time)

= 9/25×100/6=6% per annum