ShmoopTube

00:03

Here's your shmoop du jour:

00:05

A box of cards contains 23 red and 30 black cards. Must have been made in China.

00:10

How many red cards must be added so that the

00:13

proportion of red cards is 1/2?

00:16

And here are the potential answers...

00:22

So... we're not dealing with a standard deck of playing cards. Kind of hard to play

00:25

"Go Fish" with only one eight.

00:27

Okay, so here's a scale: 23 cards on the left -- red ones; 30 cards on the right -- black ones.

00:34

To get the red cards to be half of the total, or equal to the black cards...

00:39

...we need to have just as many of them as we have black cards.

00:43

We can just add 7 of 'em, and then we'll have 30 of each.

00:47

And that's all there is to it. Answer: D.

00:49

As in, "Deck of Card."

Full Transcript