# Biology Questions Answers

11) At what rate percent per annum will the simple interest on a sum of money be 2/5 of the amount in 10 ye

- 1) 1%
- 2) 2%
- 3) 3%
- 4) 4%

**Ans.**D

**Explanation :**

Let sum = x Time = 10 years. S.I = 2x /5, [as per question] Rate =( (100 * 2x) / (x*5*10))% => Rate = 4%

12) In how many years Rs 150 will produce the same interest at 8% as Rs. 800 produce in 3 years at 9

- 1) 8
- 2) 9
- 3) 10
- 4) 11

**Ans.**B

**Explanation :**

Clue: Firstly we need to calculate the SI with prinical 800,Time 3 years and Rate 9/2%, it will be Rs. 108 Then we can get the Time as Time = (100*108)/(150*8) = 9

13) Rs. 800 becomes Rs. 956 in 3 years at a certain rate of simple interest. If the rate of interest is increased by 4%, what amount will Rs. 800 become in 3 yea

- 1) Rs 1052
- 2) Rs 1152
- 3) Rs 1252
- 4) Rs 1352

**Ans.**A

**Explanation :**

S.I. = 956 - 800 = Rs 156 \begin{aligned} R = \frac{156*100}{800*3} \ R = 6\frac{1}{2}\% \ \text{ New Rate = }6\frac{1}{2}+4 \= \frac{21}{2} \% \ \text{ New S.I. = }800\times\frac{21}{2}\times{3}{100} \= 252 \end{aligned} Now amount will be 800 + 252 = 1052

14) A sum of money amounts to Rs 9800 after 5 years and Rs 12005 after 8 years at the same rate of simple interest. The rate of interest per annum

- 1) 9%
- 2) 10%
- 3) 11%
- 4) 12%

**Ans.**D

**Explanation :**

We can get SI of 3 years = 12005 - 9800 = 2205 SI for 5 years = (2205/3)*5 = 3675 [so that we can get principal amount after deducting SI] Principal = 12005 - 3675 = 6125 So Rate = (100*3675)/(6125*5) = 12%

15) A sum of money at simple interest amounts to Rs. 2240 in 2 years and to Rs. 2600 in 5 years. What is the principal amo

- 1) 1000
- 2) 1500
- 3) 2000
- 4) 2500

**Ans.**C

**Explanation :**

SI for 3 year = 2600-2240 = 360 SI for 2 year 360/3 * 2 = 240 principal = 2240 - 240 = 2000

16) Find the simple interest on the Rs. 2000 at 25/4% per annum for the period from 4th Feb 2005 to 18th April 20

- 1) Rs 25
- 2) Rs 30
- 3) Rs 35
- 4) Rs 40

**Ans.**A

**Explanation :**

One thing which is tricky in this question is to calculate the number of days. Always remember that the day on which money is deposited is not counted while the day on which money is withdrawn is counted. So lets calculate the number of days now, Time = (24+31+18) days = 73/365 years = 1/5 years P = 2000 R = 25/4% \begin{aligned} \text{ S.I. = } = \frac{2000 \times 25 }{4 \times 5 \times 100} = 25 \end{aligned}

17) Find the simple interest on Rs 7000 at 50/3 % for 9 mont

- 1) Rs. 1075
- 2) Rs. 975
- 3) Rs. 875
- 4) Rs. 775

**Ans.**C

**Explanation :**

\begin{aligned} \text{ S.I. = } \frac{P \times R \times T}{100} \end{aligned} So, by putting the values in the above formula, our result will be. \begin{aligned} \text{ Required result = } \frac{7000 \times 50 \times 9}{3 \times 12 \times 100} = 875 \end{aligned} [Please note that we have divided by 12 as we converted 9 months in a year format]

18) If A lends Rs. 3500 to B at 10% p.a. and B lends the same sum to C at 11.5% p.a., then the gain of B (in Rs.) in a period of 3 years

- 1) Rs. 154.50
- 2) Rs. 155.50
- 3) Rs. 156.50
- 4) Rs. 157.50

**Ans.**D

**Explanation :**

We need to calculate the profit of B. It will be, SI on the rate B lends - SI on the rate B gets \begin{aligned} \text{Gain of B}\\ &= \frac{3500\times11.5\times3}{100} - \frac{3500\times10\times3}{100}\= 157.50 \end{aligned}

19) A financier claims to be lending money at simple interest, But he includes the interest every six months for calculating the principal. If he is charging an interest of 10%, the effective rate of interest becom

- 1) 10.25%
- 2) 10%
- 3) 9.25%
- 4) 9%

**Ans.**A

**Explanation :**

Let the sum is 100. As financier includes interest every six months., then we will calculate SI for 6 months, then again for six months as below: SI for first Six Months = (100*10*1)/(100*2) = Rs. 5 Important: now sum will become 100+5 = 105 SI for last Six Months = (105*10*1)/(100*2) = Rs. 5.25 So amount at the end of year will be (100+5+5.25) = 110.25 Effective rate = 110.25 - 100 = 10.25

20) Sachin borrows Rs. 5000 for 2 years at 4% p.a. simple interest. He immediately lends money to Rahul at 25/4% p.a. for 2 years. Find the gain of one year by Sachi

- 1) 110.50
- 2) 111.50
- 3) 112.50
- 4) 113.50

**Ans.**C

**Explanation :**

Two things need to give attention in this question, First we need to calculate gain for 1 year only. Second, where we take money at some interest and lends at other, then we use to subtract each other to get result in this type of question. Lets solve this Simple Interest question now. \begin{aligned} \text{Gain in 2 year = } \[(5000 \times \frac{25}{4} \times \frac{2}{100})-(\frac{5000 \times 4 \times 2}{100})] \= (625 - 400) = 225 \\text{ So gain for 1 year = }\ \frac{225}{2} = 112.50 \end{aligned}