After the first, we have 2/3 left, the second and third took 1/6 and 1/4, or 5/12 (1/6+1/4=2/12+3/12=(2+3)/12=5/12). Now, we just subtract 5/12 from 2/3, so 2/3-5/12=8/12-5/12=(8-5)/12=3/12=1/4. This means we have 1/4 of an hour left.
You have to use the substitution method by substituting one Y value with the other
This is only one equation. It is therefore not a system and you can not solve for two different variables y and z unless you have another equation to solve with. It.
Let x = total sales of baked goods remember 20% = .20 as a decimal
so the equation would be .20x = $600
divide both sides by .20
.20x/.20 = $600/.20
x = $3000 the total sales of baked goods
CHECK: 20% times $3000 = .20 times $3000 = $600
8 Is the unit rate. For 9/27