Carcass wrote:
Saplings are to be planted 30 feet apart along one side of a straight line 455 feet long. If the first sapling is to be planted at one end of the lane, how many saplings are needed?
(A) 18
(B) 16
(C) \(15\frac{1}{6}\)
(D) 15
(E) 14
Let's create a table and look for a pattern.
# of trees | space needed1 tree: 0 feet
2 trees: 30 feet
[2 trees separated by the necessary 30 feet]3 trees: 60 feet
4 trees: 90 feet
5 trees: 120 feet
.
.
.
Notice that the space needed = (30)(number of trees - 1)
For example, for 5 trees we get: 120 feet = (30)(5 - 1)
So, if x = the number of trees, then
the space needed = (30)(x - 1)We know that 450 is divisible by 30, so we want:
450 = (30)(x - 1)
Divide both sides by 30 to get: 15 = x - 1
Solve: x = 16
Answer: B
Cheers,
Brent
_________________
Brent Hanneson – Creator of greenlighttestprep.com
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