SOLUTION: On Monday, Serena averaged 40 mph while making sales calls. On Tuesday, she drove for 2 hours more than she did on Monday and averaged 50 mph. If her total distance for the two day

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Question 149146: On Monday, Serena averaged 40 mph while making sales calls. On Tuesday, she drove for 2 hours more than she did on Monday and averaged 50 mph. If her total distance for the two days was 280 miles, then how many hours did she drive on Monday?
Found 2 solutions by mangopeeler07, josmiceli:
Answer by mangopeeler07(462) About Me  (Show Source):
You can put this solution on YOUR website!
x=amount of hours on Monday
coefficient=mph

40(x)+50(x+2)=280

Simplify
40+50x+100=280

Combine like terms
50x+140=280

Subtract 140 from both sides
50x=140

Divide by 50
x=2.8

She drove 2.8 hours on Monday.

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
For Monday:
d+=+r%2At
d+=+40t
For Tuesday
280+-+d+=+r%2At
280+-+d+=+50%2A%28t+%2B+2%29
This is 2 equations with 2 unknowns
280+-+40t+=+50%2A%28t+%2B+2%29
280+-+40t+=+50t+%2B+100
90t+=+180
t+=+2 hrs
She drove 2 hrs on Monday
check:
d+=+40t
d+=+40%2A2
d+=+80 mi
280+-+d+=+50%2A%28t+%2B+2%29
280+-+d+=+50%2A4
280+-+d+=+200
d+=+80 mi
OK