# Difference between revisions of "2021 AMC 12A Problems/Problem 6"

## Problem

A deck of cards has only red cards and black cards. The probability of a randomly chosen card being red is $\frac13$. When $4$ black cards are added to the deck, the probability of choosing red becomes $\frac14$. How many cards were in the deck originally?

## Solution

The solutions will be posted once the problems are posted.

See problem 1.