So I did the GMAT Prep #2 yesterday and this question has been messing with my head every since. I'm not sure if I'm not seeing it right but I have no clue how they managed to get to the answer at all. I happen to be reviewing the questions before my exam (tomorrow) and I can't seem to solve this one.
So the question goes as follows:
When a certain tree was first planted, it was 4 ft 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?
The correct answer is 2/3
My logic:
each year increase: x
If the plant was 4 ft the first year, then 6th year = 4 + 5x (as 2nd year - x, 3rd year - 2x, 4th year - 3x etc.) and 4th year = 4 + 3x
The different between both years = 1/5
So 6th - 4th = 2x
Therefore, 2x =1/5
and x = 1/10
I have been thinking and re-thinking but I have no clue how else to solve it. I'm clearly missing something obvious. Any ideas where I'm going wrong?
So the question goes as follows:
When a certain tree was first planted, it was 4 ft 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?
The correct answer is 2/3
My logic:
each year increase: x
If the plant was 4 ft the first year, then 6th year = 4 + 5x (as 2nd year - x, 3rd year - 2x, 4th year - 3x etc.) and 4th year = 4 + 3x
The different between both years = 1/5
So 6th - 4th = 2x
Therefore, 2x =1/5
and x = 1/10
I have been thinking and re-thinking but I have no clue how else to solve it. I'm clearly missing something obvious. Any ideas where I'm going wrong?
