The denominator must be the same, so just think of the LEAST COMMON MULTIPLE, The LCM here is 8, because you can multiply 4 by 2 to get 8.
so when you multiply, you multiply both on the top and on the bottom, so this would be:
3 x 2 / 4 x 2 = 6 / 8
Now you can add or subtract: 6/8 - 1/8 = 5/8
It equals 99. 4 times 9 equals 36. 11 times 9 equals 99.
I'm assuming you're supposed to find the chance of them drawing red or blue/
So the whole is 20, and red and blue combined is 14.So its 14/20, which is 70%, and as a simplified fraction it is 7/10.