In a set of magicians cards, there are 15 red cards, and 60% more green cards. Yellow cards are as many, as the sum of red and green cards. How many cards of all mentioned colors are there?
How many more green cards are there than red cards? ** There are 60/100 * 15 = <<60/100*15=9>>9 more green cards than red cards.
How many green cards are there? ** Which means there are 15 + 9 = <<15+9=24>>24 green cards.
How many cards are yellow? ** Yellow cards make up to 15 + 24 = <<15+24=39>>39 cards.
How many cards are there? ** So in total, there are 39 + 39 = <<39+39=78>>78 cards of different colors.
#### 78