CAT Questions

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The sum of the oxidation numbers in a compound must equal zero. In the compound hydrogen sulfide, H2S, the two hydrogen atoms have an oxidation number of +1, for a total of +2.

Therefore, the oxidation number of sulfur in the compound is -2, and the sum of the oxidation numbers is 0.

Tea bag is what it will go in dry and come out wet, the longer it is in, the stronger the tea we will get.

Initialy from left 7th = kumar
from right 9th = pawan
Interchange kumar = 11th from left, from right kumar = 9th;
11+8 = 19;
8 is 1,2,3,4,5,6,7(pawan),8,9,10,11(kumar),12,13,14,15,16,17,18,19;
simply count the 9th place from right we will get total as 19.

The second word is a disease of the first word.

That is here Myopia is the disease of the eyes. Similarly, Pyorrhea is the disease of the teeth.

Hence, Eye : Myopia :: Teeth : Pyorrhea.

Given total number of rats = 999919

999919 = 1000000 - 81 = 10002 - 92 = (1000+9)(1000-9) = 1009 x 991.
Since there were more rats than there were cats, 991 cats killed 1009 rats each.

Let number of boys = x  , Let number of girls = y
Total numbers of students = x + y
(x + y) × 15.8 = 16.4x + 15.4y
0.6x = 0.4y
x/y = 0.4/0.6 = 2/3

 Ratio of boys and girls in the class is 2:3