Bunuel
Fifty percent of the articles in a certain magazine are written by staff members. Sixty percent of the articles are on current affairs. If 75 percent of the articles on current affairs are written by staff members with more than 5 years experience of journalism, how many of the articles on current affairs are written by staff members with more than 5 years experience?
(1) 20 articles are written by staff members.
(2) Of the articles on topics other than current affairs, 50 percent are by staff members with less than 5 years experience.
let’s create a matrix format for staff members(sm) and current affairs (ca). Not staff members with 5+ experience and Not current affairs be NSM, NCA respectively.
given parameters :
50% of articles are written by Staff Members.
60% are on current affairs.
75% of the articles are written by SM with 5+ experience.
To find:
how many of the articles on current affairs are written by staff members with more than 5 years experience?
| | CA | NCA | |
| SM | 3/4*(6n) | 5n - 3/4*(6n) | 5n |
| NSM | 1/4*(6n) | 5n - 1/4*(6n) | 5n |
| TOTAL | 6n | 4n | 10n |
Statement 1:
(1) 20 articles are written by staff members.
Give 5n = 20 , hence n = 4
substituting the value of n, we can arrive at 3/4*(6n) = 18.
Sufficent Statement 2: (2) Of the articles on topics other than current affairs, 50 percent are by staff members with less than 5 years experience.
without knowing the value of n, we cannot calculate the exact numbers. Hence
Not sufficient
Hence, Option A