This means the for every 2 units of red paint, there is 1 unit of blue paint exg in a mixture, mix a red and blue paint to get a type of purple that is the ratio of 2:1 (red:blue) so exg if you wanted 3 gallons you would do 2 gallons of red+1 gallon of blue since 2+1=3 it could also mean quantity there are 2 tiles painted red for every 1 tile painted blue resulting in 2 unit of red paint to 1 unit of blue
Let's say that the time it took him to get to work in the morning is t hours. Then the time it took him to get home in the afternoon must be 1 - t hours. We know that for any trip, distance equals rate times time or d = rt . That means that the distance he drove to work is given by , but we also know that the distance he drove to get home must be the same distance, because he took the same route (and, presumably, no one picked up him house and moved it while he was at work) so for the trip home we can say d = 30 × (1 - t) and since the distances are equal, we can say: