Hey there!
If a cost of a gallon recently doubled, then it increased by 50%. This is because half of 100% is 50% and it takes one more 50% to double.
Hope this helps you.
Have a great day!
The answer that you should get is A
Hey! Your rational number would be 
1 Degree Radian = π (pie)/ 180 degrees
I think the probability that Gwen will reach in her book bag purple eraser is 5/20 or 1/4