Ross has 40 shirts ¾

Ross has 40 shirts, ¾ of the shirts are green and 1/10 is without buttons.
Therefore Ross has between ___ and ___ shirts with buttons that are not green.
(a) 6 ; 10.
(b) 4 ; 25.
(c) 4 ; 10.
(d) 5 ; 25.
(e) 3 ; 10.

The best answer is A.
Notice that the groups that we are looking for a overlapping are the not-green shirts and the buttoned ones. The not-green shirts are a quarter of 40, 10 shirts.
The shirts with buttons are (9/10 x 40 = 36).
The maximum overlapping is the size of the smallest group: 10.
The minimum overlapping is: 36 + 10 – 40 = 6.
Therefore A is the answer.


In the Kan film festival, 50 movies were presented. 3/5 of the movies are action movies and 4/5 is science fiction movies. How many of the movies were science fiction action movies?
(a) 10.
(b) 15.
(c) 20.
(d) 30.
(e) 35.

The best answer is C.
There were (3/5 x 50 = 30) action movies.
There were (4/5 x 50 = 40) science fiction movies.
Exact overlapping is calculated by minimum overlapping method.
Therefore there are (40 + 30 – 50 = 20) movies that belong to both categories.