GATE Questions

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Manju borrows Rs. 5000 for 2 years at 4% p.a. simple interest 

She also lends it at 6 1⁄4% p.a for 2 years 

=> Total Gain = 6 1/4% − 4% = 2 1/4%

So her gain in the transaction for 1 year

= The simple interest she gets for Rs.5000 for 1 year at 2 1⁄4% per annum

= PTR100=5000×94×1100 = Rs. 112.5/ year.

The probability of an impossible event is 0.

The event is known ahead of time to be not possible, therefore by definition in mathematics, the probability is defined to be 0 which means it can never happen.

The probability of a certain event is 1.

Let the present age of Deepa = 5p

Let the present age of Hyma = 6p

After four years their ratio = 6 : 7

=> 5p + 46p + 4 = 67

=> 35p + 28 = 36p + 24

=> p = 4

Therefore, the difference between their ages = 24 - 20 = 4 years.

Let the principle amount be Rs. P

Interest rate = 12%

Total amount he paid after 5 years = Rs. 1280

ATQ, 

$$\begin{gathered} P + I = PTR100 + P \\ 1280 = PTR100 + 1 \\ 1280 = P5 x 12100 + 1 \\ 16P10 = 1280 \\ P = 80 x 10 = 800 \end{gathered}$$

Hence, the amount he borrowed = P = Rs. 800.

Here simple coding language has been used. Each letter has been assigned a numeric code and the respective code of letters are in the same order as the letters. 

Letter      B  E  L  M  O  P  R

Code         8  7  3  5  4  2  9

 BORE -> 8497 -- correct

 MOEP -> 5472 But given 5972 --- Incorrect

 LBOR -> 3849  -- correct

OMEP -> 4572  -- correct

P1+20100n > 2P 

Now, (6/5 x 6/5 x 6/5 x 6/5) > 2.

So, n = 4 years.

Total strength of the class is given by

15 + 44 + 4 + 3 - 1 = 65

Let the age of Manisha and Sudeshna is 5x and 6x years respectively.

According to the given data,

5x+8/6x+8 = 7/8

42x + 56 = 40x + 64

x = 4

Required Difference of their ages = (6 × 4)  –  (5 × 4)

= 4 years.