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.

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%.

Sir Sandford Fleming, (January 7, 1827 – July 22, 1915) was a Scottish Canadian engineer and inventor. Born and raised in Scotland, he emigrated to colonial Canada at the age of 18. He proposed worldwide standard time zones, designed Canada's first postage stamp.

Here among the given numbers, 3, 19, 67 are prime numbers. And 133 is not a prime number.

Hence, the odd number of the given numbers is 133.

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.

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.