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The eccentric old man decided to plant a new garden.

This time, he told his gardener, I want 18 rows of at least 3 trees.

But don't waste my money.

If you buy more trees than are needed, you'll be fired.

But I am a kind man: if the garden includes an additional row

- one having 4 trees - I'll give you a raise.

[1] How many trees did the careful gardener need to buy?

[2] In what configuration did he plant them?

[3] Did he get his raise?

Edited by bonanova
remove "at least" from the problem description
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The eccentric old man decided to plant a new garden.

This time, he told his gardener, I want 18 rows of at least 3 trees.

But don't waste my money.

If you buy more trees than are needed, you'll be fired.

But to show my kindness: if you include a 19th row - with 4 trees - I'll give you a raise.

How many trees did the careful gardener need to buy,

and in what configuration did he plant them?

Assuming that trees can be in more than one 'row' at a time (otherwise the answer is trivial). I'd say that 19 is the minimum, configured as shown:

__X_X__

X_X_X_X

X_X_X_X

X_X_X_X

X_X_X__

__X_X__

four horizontal rows

four vertical rows

five diagonal rows top left to bottom right

five diagonal rows bottom left to top right

Only 18, alas - no magic 19th.

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Assuming that trees can be in more than one 'row' at a time (otherwise the answer is trivial). I'd say that 19 is the minimum, configured as shown:

__X_X__

X_X_X_X

X_X_X_X

X_X_X_X

X_X_X__

__X_X__

four horizontal rows

four vertical rows

five diagonal rows top left to bottom right

five diagonal rows bottom left to top right

Only 18, alas - no magic 19th.

The gardener's official statistician has determined that's more than needed.

Also, to clarify: a row of 4 trees is only that - it's not 1 or more rows of 3.

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I think it is possible with 15 trees but I don't know how to draw diagrams on Brainden so have represented with letters and numbers in a table for position of trees See table below.

The position represented by two dashes does not have a tree. It works if you draw it on graph paper then draw in all the vertical, horizontal and diagonal lines connecting at least three trees – 19 lines in all. The less obvious lines are lines A1-B3-C5 and E1-D3-C5. There are two lines of four trees - diagonal A1-B2-C3-E5 and E1-D2-C3-A5

A1 -- A3 -- A5

-- B2 B3 -- --

C1 C2 C3 C4 C5

-- D2 D3 -- --

E1 -- E3 -- E5

Is this the solution you were looking for?

Happy New Year! Alice

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The eccentric old man decided to plant a new garden.

This time, he told his gardener, I want 18 rows of at least 3 trees.

But don't waste my money.

If you buy more trees than are needed, you'll be fired.

But I am a kind man: if the garden includes an additional row

- one having 4 trees - I'll give you a raise.

[1] How many trees did the careful gardener need to buy?

[2] In what configuration did he plant them?

[3] Did he get his raise?

A hexagon with three on a side and one in the middle keeps your job at 13 trees. Adding one inline with ONLY one row of three gets you a raise with 14 trees.

Edited by charles1317
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A hexagon with three on a side and one in the middle keeps your job at 13 trees. Adding one inline with ONLY one row of three gets you a raise with 14 trees.

How do you get 18 rows of at least 3 trees per row?

Alice

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How do you get 18 rows of at least 3 trees per row?

Alice

My solution for a row with four trees is incorrect. It does not provide a nineteenth row. It looks like I don't get a raise. :( As for the 18 rows with 3 trees each:

post-12750-1230499685.jpg

Edited by charles1317
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My solution for a row with four trees is incorrect. It does not provide a nineteenth row. It looks like I don't get a raise. :( As for the 18 rows with 3 trees each:

Ummm, please disregard. Thats only twelve lines. :P I wascounting in both directions, not good.

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Amazing creativity has produced the following results:

I may have counted wrong here or there; if so let me know.

xucam with 19 trees:

5 rows of 2 / 11 rows of 3 / 5 rows of 4 / 2 rows of 6

Alice JH with 15 trees:

15 rows of 3 / 2 rows of 4 / 2 rows of 5

Charles1317 with 13 trees:

12 rows of 3

halfbrain with 15 trees:

19 rows of 3 / 1 row of 5

Prime with 19 trees:

9 rows of 3 / 6 rows of 4 / 3 rows of 5

Prime with 17 trees [and creative landscaping]

20 rows of 3

Halfbrain [with 15 trees] and Prime [with 17 trees] have produced the requisite 18 rows [and more!] of three trees.

Both layouts lack the bonus row of [exactly] 4 trees.

All layouts so far exceed the minimum number of trees.

Here's a hint: Charles missed it by a single tree [and 6 rows.]

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Here's a hint: Charles missed it by a single tree [and 6 rows.]

Although suggested minimum number is 12, I post my solution of 13, as I have also a bonus:

Black numbers are trees, blue numbers are rows.

Row number 15 has 4 trees (bonus)

Total 18 rows, 17x3 and 1x4

post-10474-1230628073.jpg

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Bonanova - have I misunderstood the question?

The wording is ".... I want 18 rows of at least 3 trees." and "...:if the garden includes an additional row - one having 4 trees - I'll give you a raise" so I interpreted this as meaning that

a) a total of 19 rows was needed to get the "raise", or "rise" as we call it in the UK

b) each of the first 18 rows must contain three or more trees per row (i.e one or two rows could contain more than 3 trees each if necessary)

c) the "additional row" i.e. 19th row must contain exactly 4 trees

I realised after posting my photo with 15 trees (at top of page 2), that the central tree is not necessary so have posted new photo with 14 trees numbered 1 to 14, and 19 rows (17 x 3 and 2 x 4 ). i.e. there are 18 rows with "at least 3 trees" (17 with exactly 3 trees per row and the 18th with 4). The 19th row contains exactly 4 trees as well!

post-9335-1230642412.jpg

I don't think any of the other answers posted so far, fulfil all the above criteria to get the "raise" or "rise".

Heck, these trees are driving me nuts! They must be nut trees, but I don't think either of King Juan Carlos's daughters are likely to visit me!

Happy New Year, Alice

Edited by AliceJH
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Bonanova - have I misunderstood the question?

The wording is ".... I want 18 rows of at least 3 trees." and "...:if the garden includes an additional row - one having 4 trees - I'll give you a raise" so I interpreted this as ....

Can't believe I did that.

Wait. *checks calendar* Yeah, I can believe it. :blush:

"at least" does not belong there.

It doesn't let the bonus row of 4 trees make much sense.

Wow - sorry for the headache that caused.

Now that several of you have over-achieved the stated OP,

shall I show my 18 rows of exactly 3 trees - with a bonus row of 4?

Or shall the headaches continue? ;)

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Can't believe I did that.

Wait. *checks calendar* Yeah, I can believe it. :blush:

"at least" does not belong there.

It doesn't let the bonus row of 4 trees make much sense.

Wow - sorry for the headache that caused.

Now that several of you have over-achieved the stated OP,

shall I show my 18 rows of exactly 3 trees - with a bonus row of 4?

Or shall the headaches continue? ;)

Please show @_@

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The eccentric old man decided to plant a new garden.

This time, he told his gardener, I want 18 rows of at least 3 trees.

But don't waste my money.

If you buy more trees than are needed, you'll be fired.

But I am a kind man: if the garden includes an additional row

- one having 4 trees - I'll give you a raise.

[1] How many trees did the careful gardener need to buy?

[2] In what configuration did he plant them?

[3] Did he get his raise?

58 trees unless they were sick trees, in which case, he would've been fired for wasting money anyway

18 rows of 3 and one row of 4

yes, he got his raise

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