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Here’s your shmoop du jour: A box of cards contains 23 red and 30 black
cards. Must have been made in China. How many red cards must be added so that the
proportion of red cards is 1/2? And here are the potential answers…
So… we’re not dealing with a standard deck of playing cards. Kind of hard to play
“go fish” with only one eight.
Okay, so here’s a scale: 23 cards on the left – red ones; 30 cards on the right – black
ones.
To get the red cards to be half of the total, or equal to the black cards…
…we need to have just as many of them as we have black cards.
We can just add 7 of ‘em, and then we’ll have 30 of each.
And that’s all there is to it. Answer: D.
As in, “Deck of Card.”