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Q:

Find the probability of selecting exactly 2 children when four persons are choosen at random from a group of 3 men, 2 woman and 4 children.

A) 9/29	B) 10/21
C) 12/21	D) 14/19

Answer & Explanation Answer: B) 10/21

Explanation:

4 persons can be selected from 9 in $9 C_{4}$ ways =126

Fvaourable events = $4 C_{2} * 5 C_{2}$ =60

So,required probability = 60/126 = 10/21

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Filed Under: Probability

Q:

Four persons are to be choosen from a group of 3 men, 2 women and 4 children. Find the probability of selecting 1 man,1 woman and 2 children.

A) 2/7	B) 3/7
C) 4/7	D) 3/7

Answer & Explanation Answer: A) 2/7

Explanation:

Total number of persons = 9

Out of 9 persons 4 persons can be selected in $9 C_{4}$ ways =126

1 man,1 woman and 2 children can be selected in $3 C_{1} * 2 C_{1} * 4 C_{1}$ ways =36

So,required probability = 36/126 =2/7

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Q:

A large cube is formed from the material obtained by melting three smaller cubes of 3, 4 and 5 cm side. What is the ratio of the total surface areas of the smaller cubes and the large cube?

A) 2 : 1	B) 3 : 2
C) 25 : 18	D) 27 : 20

Answer & Explanation Answer: C) 25 : 18

Explanation:

Volume of the large cube = $(3^{3} + 4^{3} + 5^{3})$ = 216 cu.cm.

Let the edge of the large cube be a.

So, $a^{3}$ = 216

=>a = 6 cm.

Required ratio = $\frac{6 (3^{2} + 4^{2} + 5^{2})}{6 (6^{2})} = \frac{25}{18}$

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Filed Under: Volume and Surface Area

Q:

What is the total surface area of a right circular cone of height 14 cm and base radius 7 cm?

A) 344.35 sq.cm	B) 462 sq.cm
C) 498.35 sq.cm	D) None of these

Answer & Explanation Answer: C) 498.35 sq.cm

Explanation:

h = 14 cm, r = 7 cm.

So, l = $[\sqrt{7^{2} + 14^{2}}] = \sqrt{245} = 7 \sqrt{5} c m$

Total surface area = $πrl + {πr}^{2}$ = $\frac{22}{7} \times 7 \times 7 \sqrt{5} + \frac{22}{7} \times 7 \times 7$

= $154 (\sqrt{5} + 1)$

= (3.236 x 154) sq.cm

= 498.35 sq.cm

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Filed Under: Volume and Surface Area

Q:

Difference between bit rate and baud rate.?

Answer

Bit rate is the number of bits transmitted during one second whereas baud rate refers to the number of signal units per second that are required to represent those bits.

baud rate = bit rate / N

where N is no-of-bits represented by each signal shift.

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Subject: Networking
Job Role: Network Engineer

Q:

What is Bandwidth?

Answer

Every line has an upper limit and a lower limit on the frequency of signals it can carry. This limited range is called the bandwidth

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Subject: Networking
Job Role: Network Engineer

Q:

A man invests some money partly in 9% stock at 96 and partly in 12% stock at 120. To obtain equal dividends from both, he must invest the money in the ratio:

A) 3:5	B) 2:1
C) 16:15	D) 4:5

Answer & Explanation Answer: C) 16:15

Explanation:

For an income of Re. 1 in 9% stock at 96, investment = Rs. 96/9 = Rs.32/3

For an income Re. 1 in 12% stock at 120, investment = Rs. 120/12 = Rs. 10.

Ratio of investments =(32/3) : 10 = 32 : 30 = 16 : 15.

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Filed Under: Stocks and Shares

Q:

The curved surface area of a cylindrical pillar is 264 sq.m and its volume is 924 cub.m. Find the ratio of its diameter to its height

A) 3 : 7	B) 7 : 3
C) 6 : 7	D) 7 : 6

Answer & Explanation Answer: B) 7 : 3

Explanation:

$\frac{{πr}^{2 h}}{2 {πr}^{2 h}} = \frac{924}{264}$

=> r = (24/364) x 2 = 7m

$2 πrh = 264 \Rightarrow h = (264 \times \frac{7}{22} \times \frac{1}{2} \times \frac{1}{7}) = 6 m$

Required Rato =2r/h =14/6 = 7:3

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Filed Under: Volume and Surface Area

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