GATE Questions

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In H2SO4,

Hydrogen has a charge of +2, with each hydrogen has +1.

Oxygen has  a charge of -8, with each oxugen has -2.

Total charge = (2 - 8) = -6

Therefore, the Oxidation number of Sulphur S is '+6' because to make the compound stable.

Let 'B' be the nuber of bricks.

=> 10 x 4/100 x 5 x 90/100 = 25/100 x 15/100 x 8/100 x B

=> 10 x 20 x 90 = 15 x 2 x B

=> B = 6000

From the given data,

3500x7xt/100 = 500

=> t = 100/49 years

Now, in the second case

The interest per year = 49/100 x 800 = 392

 => 4900 x 1 x r/100 = 392

=> r = 8%

Assume first child (the youngest) get = Rs. x

According to the question ;
each son having Rs. 30 more than the younger one

Second child will get = Rs. x + 30
Third child will get = Rs. x + 30 + 30 = x + 60
Forth child will get = Rs. x + 30 + 30 + 30 = x + 90
Fifth child will get = Rs. x + 30 + 30 + 30 + 30 = x + 120

Total amount they got = Rs. 2000

x + (x+30) + (x+60) + (x+90) + (x+120) = 2000
5x + 300 = 2000
5x = 1700
x = Rs. 340
So the youngest child will get Rs. 340.

75% of 450 + ? % of 560 = 600 

$$\begin{gathered} 75 x 450100 + ? x 560100 = 600 \\ 75 x 92 + 28p5 = 600 \\ 75x9x5 + 56p10 = 600 \\ 3375 + 56p = 6000 \\ 56p = 2625 \\ p = 46.875 \end{gathered}$$

Hence, in the given question ? = 46.875

74.99% of 1299 + 8.98% of 1899 = ? 

$$\begin{gathered} ? = 75 x 1400100 + 9 x 1800100 \\ ? = 1050 + 162 \\ ? = 1212. \end{gathered}$$

Water required = 4000 x 140 = 560000 lit = 560 cu.m (1 cu.m = 1000 lit)

Volume of tank = 18 x 12 x 8 = 1728 cu.m

Water of this tank will suffice for = 1728/560 = 3 days.