# SSC GD Constable 2015 Question Paper - Morning Shift - Elementary Mathematics Questions and Answers

## SSC GD Constable 2015 Question Paper - Morning Shift : Elementary Mathematics

**1.**16 men are able to complete a piece of work in 12 days working 14 hours a day. How long will 28 men, working 12 hours a day, take to complete the work ?

**Answer: ** C. 8 days

**Explanation: **

M1D1H1 = M2D2H2

Where M = number of Men, D = number of days and H = number of hours

Given,

M1 = 16, D1 = 12, H1 = 14, M2 = 28, H2 = 12 and D2 = ?

D2 = (16 x 12 x 14) / (28 x 12)

= 8 days

Then, 28 men working 12 hours a day, take to complete the work in 8 days.

**2.**A certain sum amounts to Rs. 1725 at 15% per annum at simple interest and Rs. 1800 in the same time at 20% per annum at simple interest. Find the sum.

**Answer: ** B. Rs. 1500

**Explanation: **

If rate of simple interest per annum = 15%, amount = Rs. 1725

And rate of simple interest per annum = 20%, amount = Rs. 1800

Then, 5% of principle = 1800-1725 = Rs. 75

Therefore, 100% priniciple = 75 x 100/5

= 75 x 20

=> Rs. 1500

Then, the principle is Rs. 1500

**3.**A dealer marks his goods 20% above cost price and allows a discount of 10% to his customers. His gain percentage is ?

**Answer: ** C. 8%

**Explanation: **

A dealer marks his goods 20% above cost price.

Then, the price of goods = 100 + 100 x 20/100

= 100+20

= 120

He gave 10% discount,

then selling price = 120 - 120 x 10/100

= 120 - 12

= Rs. 108

Gain% = 108 - 100

= 8%

Then, his gain % is 8

**4.**Raja can do a piece of work in 20 days while ramesh can finish it in 25 days. Ramesh started working and Raja joined him after 10 days. The whole work is completed in ?

**Answer: ** B. 16 2/3 days

**Explanation: **

Therefore, Raja can do a piece of work in a day = 1/20

Ramesh can do a piece of work = 25 days

Therefore, Ramesh can do a piece of work in a day = 1/25

Raja and Ramesh can do together work in a day = 1/20 + 1/25

=> 9/100

Then, Raja and Ramesh can do together work = 100/9 days

Ramesh can do a work in 10 days = 10/25

Remaining work = 1-10/25

=> 3/5

Then, Raja & Ramesh can do complete remaining work = 100 x 3/5 x 9

=> 20/3

Therefore, the whole work is complete = 10 + 20/3

=> 50/3 days

**5.**1008 divided by which single digit number gives a perfect square ?

**Answer: ** A. 7

**Explanation: **

1008 divide by 7 = 1008/7 = 144

144 is a square of 12

Now, take option (2)

1008 divide by 8 = 1008/8 = 126

126 is not a square of any number.

Take option (3)

1008 divide by 9 = 1008/9 = 112

112 is not a square of any number.

Take option (4),

1008 divide by 4 = 1008/4 = 252

252 is not a square of any number.

Hence, the answer is 7

**6.**A right circular cone of height 20 cm and base radius 15 cm is melted and casted into smaller cones of equal sizes of height 5 cm and base radius 1.5 cm. The number of casted cones are ?

**Answer: ** D. 400

**Explanation: **

Volume of cone = 1/3(Ï€r

^{2}h)

Then, volume = 1/3(Ï€ x 15

^{2}x 20)

=> 1500Ï€ cm

^{3}

The height of small cone = 5cm

Radius of small cone = 1.5 cm

Volume of small cone = 1/3(5 x 1.5 x 1.5 x Ï€)

=> 3.75Ï€ cm

^{3}

Then the number of small cones = 1500Ï€ / 3.75Ï€ => 400

Hence the number of casted cones = 400

**7.**A student starting from his house walks at a speed of 2 1/2 km/hour and reaches his school 7 minutes late. Next day starting at the same time he increases his speed by 1 km/hour and reaches 6 minutes early. The distance between school and his house is ?

**Answer: ** D. 1 3/4 km

**Explanation: **

According to question,

x(5/2) + 6/60 = x(5/2 + 1) - 6/60

2x/5 + 1/10 = 2x/7 - 1/10

(7 * 2x - 5 * 2x)/35 = -2/10

(14x - 10x)/35 = -1/5

4x = -7

x = -7/4

As, distance is never in negative

Hence, x = 7/4

Hence, the distance between the school and house is 1 3/4 km

**8.**The mean proportion of 1.21 and 0.09 is ?

**Answer: ** C. 0.33

**9.**The value of âˆš.000441 is equal to ?

**Answer: ** B. 0.021

**Explanation: **

^{1/2}= (0.021 x 0.021)

^{1/2}

=> 0.021

**10.**A batsman makes a score of 87 runs in the 17th inning and thus increased his average by 3. Find his average after 17th inning.

**Answer: ** C. 39

**Explanation: **

Then, the average after 16th innings = x-3

According to question,

16(x-3) + 87 = 17x

16x - 48 + 87 = 17x

16x + 39 = 17x

17x - 16x = 39

x = 39

Then, the average after 17th innings is 39

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