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Constant growth

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Junior | Next Rank: 30 Posts
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Constant growth

by jmtkrs10 » Thu Jul 24, 2008 10:20 pm
When a certain tree was first planted, it was 4 feet tall, and the height of the tree increased by a constant amount each year for the next 6 years. At the end of the 6th year, the tree was 1/5 taller than it was at the end of the 4th year. By how many feet did the height of the tree increase each year?

A. 3/10
B. 2/5
C. 1/2
D. 2/3
E. 6/5

OA - D

Thanks!
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Junior | Next Rank: 30 Posts
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by Saule » Thu Jul 24, 2008 10:52 pm
Solve two equations:
6x/5 - 6y = 4 and
4+4y = x , where
y is the annual growth length in feet
and x is the tree height at the end of the 4th year.

y=2/3
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by swati.sug » Thu Jul 24, 2008 11:16 pm
Suppose tree grows x every year
At end of first year height will be 4 + x

At At end of fourth year height will be 4 + 4x


At At end of sixth year height will be 4 + 6x

According to question height at end of sixth year is greater by 1/5th of height at 4th year

therefore

4+6x = (4+4x) + (4+4x)/5

Solve for x
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Junior | Next Rank: 30 Posts
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by jmtkrs10 » Fri Jul 25, 2008 7:52 am
thanks for the responses
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