GATE Questions

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Let the present age of Pinky be x years

Then the age of Mary is x - 12 years

After 3 years,

Ratio of  MaryPinky = x - 9x + 3 = 58

8x - 72 = 5x +15

=> 3x = 87

=> x = 29

=> Age of Pinky = 29 years

=> Age of Mary = 29 - 12 = 17 years

Present age of Sam = 29 + 17 = 46

Before 15 years Sam age = 46 - 15 = 31 years.

Px85100=120

=> p = 12000/85 = 141.17 %

In this chemical reaction chlorine change oxidation number from 0 to -1 (reduction) and bromine change oxidation number from -1 to 0 (oxidation).

Chlorine is stronger oxidation reagent than bromine.

In VIIA or group 17 (halogen elements) there are six elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At) and tennessin(Ts).

They have high electronegativity because they have seven valence electrons in their outermost energy level, so they can gain an electron to have the octet rule.  

Going down in the group, element are weaker oxidazing reagent and less reactive.

Total distance = 150 + 210 = 360 mts

Time taken to cross each other when moving in opposite direction = 10.8 sec

Relative speed of trains = (350/10.8) x 18/5 = 3600/30 = 120 kmph

Speed of shorter train = (150/12) x 18/5 = 45 kmph

Hence, speed of longer train = 120 - 45 = 75 kmph.

Quarter of Kg means 250 gm

Less weight, less price (Direct Proportion)

So,

250 : 200 :: 60 : x => x = 48

So 200 gm will cost 48 paise.

Let cost of each cell phone = Rs.100 & Sale = 100 phones.

Money receipt = Rs.(100 x 100) = Rs.10,000

New cost per cellphone = Rs.120 and New sale = 70 phones

New Money Receipt = Rs.(70 x 120) = Rs.8400

Then the effect of sales = decrease in money receipt = 

160010000 x 100 = 16%.

Given that, a woman has seven children. Half of them are boys. 

Half of 7 is 3.5 which is not possible. And it is possible in only one way that all the children must be boys. Then half of them are boys.