If a+b=5 and 3a+2b=20,then (3a+b)will be :

Q:

If a + b + c = 13, $a^{2} + b^{2} + c^{2} = 69$ then find the ab + bc + ca :

A) 10	B) 30
C) 50	D) 70

Answer & Explanation Answer: C) 50

Explanation:

${(a + b + c)}^{2} = a^{2} + b^{2} + c^{2} + 2 (a b + b c + c a)$

$2 (a b + b c + c a) = {(a + b + c)}^{2} - (a^{2} + b^{2} + c^{2}) = 169 - 69 = 100 = (a b + b c + c a) = 50$

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51 27252

Q:

The total of 324 of 20 paise and 25 paise make a sum of Rs. 71. The no of 20 paise coins is :

A) 50	B) 100
C) 150	D) 200

Answer & Explanation Answer: D) 200

Explanation:

Let the number of 20 paise coins be x. Then the no of 25 paise coins = (324 - x).

0.20 * (x) + 0.25 (324 - x) = 71 => x = 200..

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19 15160

Q:

Water boils at 212°F or 100°C and melts at 32°F or 0°C . If the temparature of the particular day is 35°C , it is equal to :

A) 85°F	B) 95°F
C) 96°F	D) 97°F

Answer & Explanation Answer: B) 95°F

Explanation:

Let F and C denotes the temparature in Fahrenheit anid Celcsius respectively.

Then, (F - 32) /(212 - 32) = (C - 0)/(100 - 0), if c = 35, then F = 95.

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6 7923

Q:

If x = 1 - q and y = 2q + 1, then for what value of q, x is equal to y ?

A) 0	B) 1
C) -1	D) -2

Answer & Explanation Answer: A) 0

Explanation:

x = y <=> 1 - q = 2q + 1 <=> 3q = 0 <=> q = 0.

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8 7240

Q:

What is value of $\frac{P + Q}{P - Q}$ if $\frac{P}{Q} = 7$ ?

A) 1/3	B) 2/3
C) 4/3	D) 5/3

Answer & Explanation Answer: C) 4/3

Explanation:

$h e n c e P = 7 Q$

$\frac{P + Q}{P - Q} = \frac{7 Q + Q}{7 Q - Q} = \frac{8 Q}{6 Q} = \frac{4}{3}$

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1 4897

Q:

If $\frac{a}{b} = \frac{4}{5}$ and $\frac{b}{c} = \frac{15}{16}$ , then $\frac{c^{2} - a^{2}}{c^{2} + a^{2}}$ is :

A) 7/5	B) 7/25
C) 7/125	D) 7

Answer & Explanation Answer: B) 7/25

Explanation:

$\frac{a}{b} \times \frac{b}{c} = \frac{4}{5} \times \frac{15}{16} = \frac{3}{4} = \frac{16 - 9}{16 + 9}$

= $\frac{7}{25}$

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7 7079

Q:

If a * b = 2a - 3b + ab, then 3 * 5 + 5 * 3 is equal to :

A) 22	B) 23
C) 24	D) 25

Answer & Explanation Answer: A) 22

Explanation:

3 * 5 + 5 * 3 = (2 * 3 - 3 * 5 + 3 * 5) + ( 2 * 5 - 3 * 3 + 5 * 3)

= (6 + 10 - 9 + 15) = 22.

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84 35807

Q:

By how much is three-fifth of 350 greater than four-seventh of 210 ?

A) 90	B) 100
C) 110	D) 120

Answer & Explanation Answer: A) 90

Explanation:

3/5 of 350 - 4/7 of 210 = 210 - 120 = 90.

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16 9417

A) 20	B) 15
C) 25	D) 30

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