SOLUTION: Can you explain the correct way to work this systems of linear equations word problem out? Thanks! Problem: A bricklayer begins work at 7 a.m., laying 170 bricks per hour. Tw

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Can you explain the correct way to work this systems of linear equations word problem out? Thanks! Problem: A bricklayer begins work at 7 a.m., laying 170 bricks per hour. Tw      Log On


   

Question 371294: Can you explain the correct way to work this systems of linear equations word problem out? Thanks!
Problem: A bricklayer begins work at 7 a.m., laying 170 bricks per hour. Two hours later his apprentice joins him and lays 80 bricks per hour. At what time will they have laid 965 bricks?
Found 2 solutions by stanbon, ewatrrr:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Problem: A bricklayer begins work at 7 a.m., laying 170 bricks per hour. Two hours later his apprentice joins him and lays 80 bricks per hour. At what time will they have laid 965 bricks?
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Apprentice DATA:
rate = 80 b/h ; time = x hrs ; work done = 80x bricks
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Bricklayer DATA:
rate = 170 b/h ; time = x+2; ; work done = 170(x+2) bricks
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Equation:
bricks + bricks = 965 bricks
80x + 170(x+2) = 965
80x + 170x + 340 = 965
250x = 625
x = 2.5 hrs
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x+2 = 4.5 hrs
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Time: 7 am + 4.5 hrs = 11:30 am (time they finish the work)
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Cheers,
Stan H.

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi,

Let x represent the hours bricklayer beginning work at 7 a.m works.

Then (x-2)represents the hours for the other bricklayer

170/hr*x +80/hr*(x-2) = 965

solving for x

170x + 80x - 160 = 965

250x = 1125

x = 4.5 hrs, time worked for bricklayer beginning work at 7 a.m.

11:30 am wil be the time the work is finished.