GRE Questions

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The letters move 2, 2, 3, 3, 4, 4, ... steps forward.

Indian stamps are common to both ratios. Multiply both ratios by factors such that the Indian stamps are represented by the same number.

US : Indian = 5 : 2, and Indian : British = 5 : 1. Multiply the first by 5, and the second by 2. 

Now US : Indian = 25 : 10, and Indian : British = 10 : 2

Hence the two ratios can be combined and US : British = 25 : 2

The given number series 999, 990, 998, 991, 997, 992, ?

It follows a pattern that,

999

999 - 9 = 990

990 + 8 = 998

998 - 7 = 991

991 + 6 = 997

997 - 5 = 992

992 + 4 = 996

Hence, the next number in the given number series is 996.

How many times can you subtract 10 from 100, for this if we go through logically, it is only 1 time. For the first time if we subtract 10 from 100, then there will no 100 to subtract from.

Hence, it is only 1 time we can subtract 10 from 100.

The best approach is to pick a number that satisfies the rules that x and y are greater than 0. So for example you could choose 25 for y.

The value of x before doubling is then 25 - 50/25 = 23

The value after doubling y will be 50 - 50/50 = 49, which is more than double.

Brightness of bulb depends on both voltage and current. The brightness depends on power.

Since we know that  Power (P) = Voltage x Current = V I

So whether you increase the current or the voltage the brightness will increase.

Example Illustration:

 If you connect a long bulb and a round bulb in series, the long bulb glows but the round bulb does not. Both of them have the same current flowing through them (they are in series) but the long bulb has a greater voltage across it because it has more resistance (even though V= IR is not obeyed exactly, voltage drop does depend on the resistance). If you connect a round bulb and a long bulb in parallel, however, it is the round bulb that is brighter because now the voltage across both bulbs is the same but the current is larger through the round bulb (smaller resistance).

Hence, the brightness of a bulb depends on power i.e, both voltage and current.

Step 1 :2x + 5y

Step 2 :3(2x + 5y) = 6x + 15y

Step 3 :(6x + 15y) - (x +y) = 6x + 15y - x - y (watch that last minus sign!)

This gives 5x + 14y

Only one such symbol is there in the given arrangement.

It is 4@5.