Emil used 3/4 of a red bottle of paint and 1/5 of a blue bottle of paint in art class. how much paint did he use in all?

First change the fraction to decimals or common denominators.

3/4 = 0.75 and 1/5 = 0.2

0.75 + 0.2 = 0.95 = 95/100 = 19/20

(3/4) = (15/20)

(1/5) = (4/20)

(15/20) + (4/20) = 19/20

3/4+1/5=19/20

Multiply 4 by 5 to get a LCD and 20 will be your new denominator,

Multiply the 3 by 5 and put that as the numerator of the new first fraction

(3/4) * 5/5=15/20

Multiply the 5 by 4 to get 20 and that will be the denominator of the second fraction, the multiply 1 by 4 and put that over the denominator,

(1/5) * 4/4=4/20

Now you can just add across,

15/20+4/20=19/20.