CAT 1991 — QA Question 32
Answer the following questions based on the information given below:
There were a hundred schools in a town. Of these, the number of schools having a play – ground was 30, and these schools had neither a library nor a laboratory. The number of schools having a laboratory alone was twice the number of those having a library only. The number of schools having a laboratory as well as a library was one fourth the number of those having a laboratory alone. The number of schools having either a laboratory or a library or both was 35.
x, y and z are three positive integers such that x > y > z. Which of the following is closest to the product xyz?
Answer & solution
(x - 1)yz
- B
x(y - 1)z
- C
xy(z - 1)
- D
x(y + 1)z
Going by the options:
(a) (x - 1)yz = xyz − yz
(b) x(y - 1)z = xyz - xz
(c) xy(z - 1) = xyz - xy
(d) x(y + 1)z = xyz + xz
Here, yz will be minimum out of yz, xz, xy, xz as x > y > z
Hence, option (a).