SOLUTION: Two crews are digging an 800-meter tunnel through Marble Mountain. Crew A starts at the west end and digs at a rate of 9m/day. Five days later, Crew B starts at a rate of 10m/day.

Question 842047: Two crews are digging an 800-meter tunnel through Marble Mountain. Crew A starts at the west end and digs at a rate of 9m/day. Five days later, Crew B starts at a rate of 10m/day. How many days will Crew A have been working when the tunnel is finished?
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
Two crews are digging an 800-meter tunnel through Marble Mountain.
Crew A starts at the west end and digs at a rate of 9m/day.
Five days later, Crew B starts at a rate of 10m/day.
How many days will Crew A have been working when the tunnel is finished?
:
Let t = no. of days dug by crew A
Crew B starts 5 days later, therefore
(t-5) = no. of days dug by crew B
:
9t + 10(t-5) = 800
Find t
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