SOLUTION: In a lighthouse, the light beam rotates once every minute to scan the area of land and ocean. If the land covers the angle of 150 degrees, how many seconds will it take to cover th

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Question 270656: In a lighthouse, the light beam rotates once every minute to scan the area of land and ocean. If the land covers the angle of 150 degrees, how many seconds will it take to cover the area of ocean.
Found 3 solutions by Greenfinch, josmiceli, mananth:
Answer by Greenfinch(383) About Me  (Show Source):
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It is moving 360 degrees in 60 seconds or 6 degrees/second.
Ocean covers 360 - 150 degrees = 210 degrees
So ocean takes 210/6 seconds = 35 seconds

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
since 150 + 210 = 360
time to scan ocean/time to scan land = 210/150
210%2F150+=+7%2F5
If t = time in minutes to scan ocean, then
1+-+t = time in minutes to scan land
7%2F5+=+t%2F%281-t%29
Multiply both sides by 5%2A%281-t%29
7%2A%281-t%29+=+5t
7+-+7t+=+5t
12t+=+7
t+=+7%2F12 min
%287%2F12%29%2A60+=+35
It takes 35 sec to scan the ocean


Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
the beam covers 360 deg in 60 seconds
150 deg is the land coverage
210 deg will be the ocean coverage
total coverage is 360 degrees ie; one revolution
150/360 is the land portion which is covered in 150/360 * 60
= 25 seconds
the ocean will be covered in 35 seconds.