2 ) For x to be integer, maximum value of x^2 should be a perfect square i.e 81 and minimum value of x^2 16
so maximim value ox x^2 = 81 , hence x = 9
similarly minimum value of x^2 = 16 hence x = 4
maximim value ox x^2 - minimum value of x^2 = 9-4 =5
Answer A
3 ) Since Fanny and alexander are travelling towards each other they travel for the same amount of time say 't' and sum of the distance traveled by them is equal to 360
hence 65t+25t = 360
90t = 360
t = 4 hrs
hence when they meet each would have traveled for 4 hrs. 1.5 hrs before they meet, each would travel for 2.5 hrs.
distance traveled by Fanny in 2.5 hrs= 25* 5/2 = 125/2 miles
distance traveled by Alex in 2.5 hrs= 65* 5/2 = 325/2 miles
therfore 1.5 hrs before they meet, distance traveled by them is
125/2+325/2 = 450/2 = 225 miles
Hence they will be 360-225 = 135 miles apart
Answer E
4) we can find the values of y-x at the boundaries of the given inequality
x=-3 y=-7 y-x = -7-(-3) = -4
x=5 y=-7 y-x = -7-5 = -12
x=-3 y=9 y-x = 9-(-3) = 12
x=5 y=9 y-x = 9-5 =4
minimum value of y-x is greater than -12 and maximim value less than 12
Answer D
7) Lets say set A has 36 numbers
2/9*36 = 8 numbers were 'observed' and remaining 36-8 = 28 numbers 'not observed'
3/4*8 = 6 of the 'observed' numbers were non negative.
Hence 8-6 =2 of the 'observed' numbers were negative
Ratio of Negative numbers/Non-negative numbers = 2/1
So out of 36 numbers 2/3 rd should be negative i.e 2/3*36 = 24 negative numbers
Total negative numbers in set A= 24
2 of the observed numbers are negative , hence from the remaining 'not observed' numbers 22 should be negative
fraction of the remaining numbers in set A that must be negative = 22/28 = 11/14
Answer A
8) there are 15 black chips and 5 white chips lets say first chip picked is black. second one is white..
hence third pick (either black or whote)would gurantee that 2 chips are of same color
Answer A
9) the pattern is blue, white, red, green, black, yellow, pink (total 7 colors)
Since the row begins with blue marble and ends with red marble the number of marbles would repeat for every 7th marble from red
3 10 17 24 31 38 45
Hence D
12) To find minimum value of x^2*y , both x^2 and y should be minimum
minimum value of y is -1/2
since x^2 is positive , minimum value of x^2 would be when x is -1/5
hence x^2 = (-1/5)^2*-1/4 = 1/25*-1/2 = -1/50
Answer B