Cara has 60 marbles, 20 of which are yellow.
The number of green marbles is half the number of yellow marbles, so there are 20/2 = 10 green marbles.
The remaining marbles are equally divided between red and blue, so there are (60 - 20 - 10) / 2 = 15 marbles of each color.
The odds of picking a blue marble out of the total marbles is 15/60 = 1/4.
To express this as a percentage, we multiply by 100 to get 1/4 * 100 = 25%.
The odds of picking a blue marble are 25%.
#### 25
The answer is: 25
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
Cara has 60 marbles in a bag. 20 of them are yellow, half as many are green, and the remaining marbles are equally divided between red and blue. If Cara picks a marble at random, what are the odds it's blue (expressed as a percentage)?

### Answer:
