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Four cards lie on table. Each card has a number printed on one side and a colour on the other. The faces visible on the cards are $2,3,$ red, and blue.

Proposition: If a card has an even value on one side, then its opposite face is red.

The card which MUST be turned over to verify the above proposition are

  1. $2,$ red
  2. $2,3,$ red
  3. $2,$ blue
  4. $2,$ red, blue
in Numerical Ability by Boss (45.8k points)
edited by | 43 views
Migrated from GO Civil 2 months ago by Arjun

1 Answer

+2 votes
Best answer

 If a card has an even value on one side, then its opposite face is red.

to verify this proposition:

  • the card with even number must be turned to check whether the opposite face is red or not.
  • If the face of the card is other then red colour, it's opposite face must not be even number, so this needs to be checked.
  • If a card face is of red colour, the opposite side may contain any number, so checking this card is needless.
  • If a card face contains an odd number, checking the opposite side colour is needless.

So, cards containing 2 at face & card with face colour Red needs to be turned to verify the proposition.

Hence, Option "C" is the correct choice.

by Boss (14k points)
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