Bunuel
If x, y, and z are consecutive positive integers, with x < y < z and x + y + z an even number, which of the following could be the value of z ?
(A) 1
(B) 2
(C) 4
(D) 5
(E) 8
Least value of x = 1, y = 2 & z = 3 {Since they are positive integers}
Also, x = z - 2, y = z - 1
--> x + y + z = z - 2 + z - 1 + z
= 3z - 3 --> This is only even when z is odd {3*odd - 3 = odd - odd = Even}
Only Option feasible = 5
IMO Option D
Bunuel
A dressing recipe calls for vinegar and oil to be in the ratio 2 : 3 by volume, and for water and oil to be in the ratio 5 : 7 by volume. If there are no other ingredients in the recipe, which of the following statements must be true?
I. The dressing will contain more water than vinegar.
II. At least 25% of the dressing will be vinegar.
III. If you have equal volumes of each ingredient, the amount of dressing you can mix will be limited by the amount of oil.
A. I only
B. II only
C. III only
D. I and II only
E. I, II and III
Given,
v:o = 2:3
o:w = 7:5
Take LCM of common ingredient oil = LCM(3, 7) = 21
--> v:o = 2:3 = 14:21
--> o:w = 7:5 = 21:15
--> v:o:w = 14:21:15
--> Values of v = 14k, o = 21k, w = 15k for any constant k.
I. The dressing will contain more water than vinegar. -
YES II. At least 25% of the dressing will be vinegar.
% Vinegar = \(\frac{14k}{(14k + 21k + 15k)}\)*100 = \(\frac{14}{50}\)*100 = 28% -
YESIII. If you have equal volumes of each ingredient, the amount of dressing you can mix will be limited by the amount of oil.
Equal Volumes of each --> v = o = w = 14k
--> It will be limited by vinegar (Least value) -
NOIMO Option D
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