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
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