Answer:50212.5
Step-by-step explanation:
For starters, create an equation to show David's earnings. We can do this using Danielle's as a basis, which is set up as y=(# of hours)x+(bonus). This gives us y=12x+80. Now, as we need both their ys to be equal, we just set both equations equal to each other, making 15x+50=12x+80. Now, we solve for x, starting with 15x+50=12x+80, subtracting 12x from both sides to get 3x+50=80, subtracting 50 from both sides to get 3x=30, and dividing three from both sides to get x=10. To check, we just plug in our answer to both equations and see if the ys match up. With Danielle's equation, we get y=15(10)+50=150+50=200 and with David's equation, we get y=12(10)+80=120+80=200, proving that our answer is correct.
Multiply equation II by 2 and then add up the equations.
8.3 : anything multiplied by one is itself
Answer:
Step-by-step explanation:
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:
45t = 30 × (1 - t)
45t = 30 - 30t
45t + 30t = 30
75t = 30
t = 30/75
t = 2 /5 hour to drive to work at 45mph
Since , d = rt
d = 45 ×(2/5) = 18miles
