chetan2u wrote:

ritu1009 wrote:

x and y are positive integers such that x + 2y > 20 and 3x – 30 < -y. What is the positive difference between the minimum possible value of x and minimum value of y?

A. -6

B. 0

C. 1

D.4

E.6

Let's get both terms in just one variable..

x+2y>20...(I)

3x-30<-y or -y>3x-30.... Multiply this with 2

-2y>6x-60.....(ii)

Add I and ii...

x+2y-2y>20+6x-60........x>6x-40..........5x<40.........x<8

So minimum value of x can be 1, as x is positive integer

Now to get minimum value of y, take x as maximum that is 7 and substitute in (I)

x+2y>20..7+2y>20....y>13/2, ao y can have minimum possible value as 7, the next integer after 13/2

Difference between the two = 7-1=6

E

I did not understand this statement:Now to get minimum value of y, take x as maximum that is 7 and substitute.

Why should we take ma of x ?

What is we assume that x and y are both 1,won't that satisfy the inequalities and answer is 0.Please let me know ,where i am wrong in this approach.

_________________

Thanks,

Ankit

Target Score:730+

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