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The compound interest on Rs. 30,000 at 7% per annum is Rs. 4347. The period (in years) is:

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Question:
The compound interest on Rs. 30,000 at 7% per annum is Rs. 4347. The period (in years) is:

[A].

2

[B].

2 1
2

[C].

3

[D].

4

Answer: Option A

Explanation:

Amount = Rs. (30000 + 4347) = Rs. 34347.

Let the time be n years.

Then, 30000 1 + 7 n = 34347
100
107 n = 34347 = 11449 = 107 2
100 30000 10000 100

n = 2 years.

The difference between simple interest and compound on Rs. 1200 for one year at 10% per annum reckoned half-yearly is:

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Question:
The difference between simple interest and compound on Rs. 1200 for one year at 10% per annum reckoned half-yearly is:

[A].

Rs. 2.50

[B].

Rs. 3

[C].

Rs. 3.75

[D].

Rs. 4

Answer: Option B

Explanation:

S.I. = Rs 1200 x 10 x 1 = Rs. 120.
100
C.I. = Rs. 1200 x 1 + 5 2 – 1200 = Rs. 123.
100

Difference = Rs. (123 – 120) = Rs. 3.

What is the difference between the compound interests on Rs. 5000 for 1 years at 4% per annum compounded yearly and half-yearly?

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Question: What is the difference between the compound interests on Rs. 5000 for 1 years at 4% per annum compounded yearly and half-yearly?

[A].

Rs. 2.04

[B].

Rs. 3.06

[C].

Rs. 4.80

[D].

Rs. 8.30

Answer: Option A

Explanation:

C.I. when interest
compounded yearly    
= Rs. 5000 x 1 + 4 x 1 + x 4
100 100
= Rs. 5000 x 26 x 51
25 50
= Rs. 5304.
C.I. when interest is
compounded half-yearly
= Rs. 5000 x 1 + 2 3
100
= Rs. 5000 x 51 x 51 x 51
50 50 50
= Rs. 5306.04

Difference = Rs. (5306.04 – 5304) = Rs. 2.04

A bank offers 5% compound interest calculated on half-yearly basis. A customer deposits Rs. 1600 each on 1st January and 1st July of a year. At the end of the year, the amount he would have gained by way of interest is:

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Question: A bank offers 5% compound interest calculated on half-yearly basis. A customer deposits Rs. 1600 each on 1st January and 1st July of a year. At the end of the year, the amount he would have gained by way of interest is:

[A].

Rs. 120

[B].

Rs. 121

[C].

Rs. 122

[D].

Rs. 123

Answer: Option B

Explanation:

Amount
= Rs. 1600 x 1 + 5 2 + 1600 x 1 + 5
2 x 100 2 x 100
= Rs. 1600 x 41 x 41 + 1600 x 41
40 40 40
= Rs. 1600 x 41 41 + 1
40 40
= Rs. 1600 x 41 x 81
40 x 40
= Rs. 3321.

C.I. = Rs. (3321 – 3200) = Rs. 121

What will be the compound interest on a sum of Rs. 25,000 after 3 years at the rate of 12 p.c.p.a.?

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Question:
What will be the compound interest on a sum of Rs. 25,000 after 3 years at the rate of 12 p.c.p.a.?

[A].

Rs. 9000.30

[B].

Rs. 9720

[C].

Rs. 10123.20

[D].

Rs. 10483.20

Answer: Option C

Explanation:

Amount
= Rs. 25000 x 1 + 12 3
100
= Rs. 25000 x 28 x 28 x 28
25 25 25
= Rs. 35123.20

C.I. = Rs. (35123.20 – 25000) = Rs. 10123.20

Albert invested an amount of Rs. 8000 in a fixed deposit scheme for 2 years at compound interest rate 5 p.c.p.a. How much amount will Albert get on maturity of the fixed deposit?

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Question: Albert invested an amount of Rs. 8000 in a fixed deposit scheme for 2 years at compound interest rate 5 p.c.p.a. How much amount will Albert get on maturity of the fixed deposit?

[A].

Rs. 8600

[B].

Rs. 8620

[C].

Rs. 8820

[D].

None of these

Answer: Option C

Explanation:

Amount
= Rs. 8000 x 1 + 5 2
100
= Rs. 8000 x 21 x 21
20 20
= Rs. 8820.

A watch which gains 5 seconds in 3 minutes was set right at 7 a.m. In the afternoon of the same day, when the watch indicated quarter past 4 o’clock, the true time is:

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Question:
A watch which gains 5 seconds in 3 minutes was set right at 7 a.m. In the afternoon of the same day, when the watch indicated quarter past 4 o’clock, the true time is:

[A].

59 7 min. past 3
12

[B].

4 p.m.

[C].

58 7 min. past 3
11

[D].

2 3 min. past 4
11

Answer: Option B

Explanation:

Time from 7 a.m. to 4.15 p.m. = 9 hrs 15 min. = 37 hrs.
4

3 min. 5 sec. of this clock = 3 min. of the correct clock.

37 hrs of this clock = 1 hrs of the correct clock.
720 20
37 hrs of this clock = 1 x 720 x 37 hrs of the correct clock.
4 20 37 4

      = 9 hrs of the correct clock.

The correct time is 9 hrs after 7 a.m. i.e., 4 p.m.

A watch which gains uniformly is 2 minutes low at noon on Monday and is 4 min. 48 sec fast at 2 p.m. on the following Monday. When was it correct?

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Question:
A watch which gains uniformly is 2 minutes low at noon on Monday and is 4 min. 48 sec fast at 2 p.m. on the following Monday. When was it correct?

[A].

2 p.m. on Tuesday

[B].

2 p.m. on Wednesday

[C].

3 p.m. on Thursday

[D].

1 p.m. on Friday

Answer: Option B

Explanation:

Time from 12 p.m. on Monday to 2 p.m. on the following Monday = 7 days 2 hours = 170 hours.

The watch gains 2 + 4 4 min. or 34 min. in 170 hrs.
5 5
Now, 34 min. are gained in 170 hrs.
5
2 min. are gained in 170 x 5 x 2 hrs = 50 hrs.
34

Watch is correct 2 days 2 hrs. after 12 p.m. on Monday i.e., it will be correct at 2 p.m. on Wednesday.

At what time between 5.30 and 6 will the hands of a clock be at right angles?

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Question:
At what time between 5.30 and 6 will the hands of a clock be at right angles?

[A].

43 5 min. past 5
11

[B].

43 7 min. past 5
11

[C].

40 min. past 5

[D].

45 min. past 5

Answer: Option B

Explanation:

At 5 o’clock, the hands are 25 min. spaces apart.

To be at right angles and that too between 5.30 and 6, the minute hand has to gain (25 + 15) = 40 min. spaces.

55 min. spaces are gained in 60 min.

40 min. spaces are gained in 60 x 40 min = 43 7 min.
55 11
Required time = 43 7 min. past 5.
11

At what time between 4 and 5 o’clock will the hands of a watch point in opposite directions?

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Question:
At what time between 4 and 5 o’clock will the hands of a watch point in opposite directions?

[A].

45 min. past 4

[B].

40 min. past 4

[C].

50 4 min. past 4
11

[D].

54 6 min. past 4
11

Answer: Option D

Explanation:

At 4 o’clock, the hands of the watch are 20 min. spaces apart.

To be in opposite directions, they must be 30 min. spaces apart.

Minute hand will have to gain 50 min. spaces.

55 min. spaces are gained in 60 min.

50 min. spaces are gained in 60 x 50 min. or 54 6 min.
55 11
Required time = 54 6 min. past 4.
11