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 2/5 taller than it was at the end of the 4th year. By how many feet did the height of the tree increase each year?	Pick
A) 3/10 B) 2/5 C) 1/2 D) 4 E) 6/5
Say, the tree grows by x feet every year.   Then, 4 + 6x = (1+2/5)(4+4x)   or, x = 4   Answer 4
<result>D</result>
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 2/5 taller than it was at the end of the 4th year. By how many feet did the height of the tree increase each year?