Two interesting GMAT Questions - please help me solve 'em

[esseisle]

A rectangular tiled floor is composed of 70 square tiles.The rectangular floor is being rearranged so that 2 tiles will be removed from each row of tiles and 4 more rows of tiles will be added.After the change in layout the floor will still have 70 tiles,and it will still be a rectangle How many rowswere in the tile before change of layout?


a. 4
b. 6
c. 10
d. 14
e. 28

answer is 6


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a ranch has both horses and ponies ,exactly 5/6 ponies have horseshoes.Half of the ponies with horseshoes are Icelandic ponies.What is the min. numner of ponies on the ranch?


a.6
b.8
c.12
d.18
e.24

[samratisking]

Originally Posted by esseisle

A rectangular tiled floor is composed of 70 square tiles.The rectangular floor is being rearranged so that 2 tiles will be removed from each row of tiles and 4 more rows of tiles will be added.After the change in layout the floor will still have 70 tiles,and it will still be a rectangle How many rowswere in the tile before change of layout?


a. 4
b. 6
c. 10
d. 14
e. 28

answer is 6


--------


a ranch has both horses and ponies ,exactly 5/6 ponies have horseshoes.Half of the ponies with horseshoes are Icelandic ponies.What is the min. numner of ponies on the ranch?


a.6
b.8
c.12
d.18
e.24

Hi esseisle,

1) This question is bit misleading. There it's given that the total tiles are 70. You have given the answer, that is the number of tiles present before the change in the layout as 6. can you explain me, how you can arrange 70 items in 6 rows? Its not possible. Either the answer is wrong or the question is.

2) This is a very good example of giving the numbers to be taken as integers rather than some fractions, because here you are dealing with the number of Ponies and Horses, which can only be given in integers and not as some 1/2 pony or 3/4 horses....

So coming to the given details,.....It's given that the 5/6th for the ponies have horseshoes. Consider the min number of ponies as X. No as per the given data, X should be an integer divisible by 6. So till now the min is 6. Now it's given that half of the ponies with horseshoes i.e.., 5/12th of total ponies are some icelandic ponies. So now the min number of ponies has increased to 12.

So the answer is 12......

Any suggestions or clarifications are welcome......


Thanks a lot!!!!!

[GmatRup]

1) answer is 'C'

here we get 2 equations
RC = 70 ---- (1)
(R-2)(C+4) = 70 ---- (2)

solving (1) & (2) we get R = 7 & C = 10


2) answer is C. Here,
5/6 (Ponies) = (Ponies having shoe horses) ---- (1)

(Ponies having shoe horses) / 2 = (Icelandic Ponies) ---- (2)

solving (1) & (2) we get,

(Icelandic Ponies) = 5 (Ponies) / 12 ---- (3)

Hence, The total number of ponies has to be divided 12

looking at the choices we get Ponies to be equals to C & E.

But we have to select the minimum as asked by the questions, hence answer is C

[firstgmat]

For the first question, i think the easier approach is to take the factors of 70
which are as follows:

• 2 * 35
• 5 * 14
• 7 * 10

The arrangement before and after has to be one of the three and the only combination satisfying all the conditions is 7 * 10 before and 5 * 14 after.

Therefore, ans is 10.

[arindambanerji]

For 1st question

If number of rows initially = r
no of coloumns = c

then we get r x c = 70

now after reorganising..we remove 2 tiles from each row..this means reducing the columns by 2, hence c-2 and increasing rows by 4, hence r+4

so after redesigning

(c-2) x (r+4) = 70

solving these two equations we get r = 10. The answer is wrong

[arindambanerji]

C 12 ponies...LCM of 6 and 12

[ravi4kiran]

the min number of ponies should be 12, as in the equation
I=(5p)/12, I will be multiple of 12
I= num of icelandic ponies
p = mum of ponies


Ans to the first is 10, best method is to factorize 70, and back substitute.
Cheers