Re: A math teacher has 30 cards, each of which is in the shape of a geomet
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17 Jul 2021, 08:49
Squares can be both rectangles and rhombuses.
So, we can solve this question as we solve questions of sets.
Rectangles = 15
Rhombuses = 10
Squares = both rectangles and rhombuses = 8
Hence, number of figure which are at least one of these shapes = 15+10 - 8 = 17
Therefore, the number of remaining figures, all of which may be circles = 13
The correct answer is E.