geometry

This topic has expert replies
Master | Next Rank: 500 Posts
Posts: 123
Joined: Mon Feb 07, 2011 12:11 pm
Followed by:1 members

geometry

by rupsk » Thu Jul 28, 2011 8:17 am
A rectangle is such that it can be perfectly cut into smaller squares of a maximum possible side of length 12 units. It is also known that the perimeter of such a rectangle is 384 units.How many distinct rectangles are there which satisfy the criteria given?

A. 4
B. 8
C. 6
D. 5
E. 12
Source: — Problem Solving |

Junior | Next Rank: 30 Posts
Posts: 20
Joined: Thu Feb 17, 2011 9:13 am
Thanked: 1 times

by sharmishtha_goel » Thu Jul 28, 2011 9:16 am

Master | Next Rank: 500 Posts
Posts: 123
Joined: Mon Feb 07, 2011 12:11 pm
Followed by:1 members

by rupsk » Thu Jul 28, 2011 9:19 am
can you explain how you have reached to this number?

Newbie | Next Rank: 10 Posts
Posts: 3
Joined: Thu Jul 28, 2011 9:29 am

by tryingtobeat » Thu Jul 28, 2011 9:34 am
Actually I misread the question. Distinct rectangles...
Last edited by tryingtobeat on Thu Jul 28, 2011 9:42 am, edited 3 times in total.

Master | Next Rank: 500 Posts
Posts: 123
Joined: Mon Feb 07, 2011 12:11 pm
Followed by:1 members

by rupsk » Thu Jul 28, 2011 9:36 am
your answer is correct but I do not agree with the logic.

Junior | Next Rank: 30 Posts
Posts: 20
Joined: Thu Feb 17, 2011 9:13 am
Thanked: 1 times

by sharmishtha_goel » Thu Jul 28, 2011 12:04 pm
rupsk wrote:A rectangle is such that it can be perfectly cut into smaller squares of a maximum possible side of length 12 units. It is also known that the perimeter of such a rectangle is 384 units.How many distinct rectangles are there which satisfy the criteria given?

A. 4
B. 8
C. 6
D. 5
E. 12

Explaination:

2(l + w) = 384
l + w = 192

as each sq that is cut from it has a length of 12 , therefore both l and w should be multiples of 12.

l = 12a
w = 12b

12a + 12b = 192
12(a+ b)= 12*16
a+ b =16
dimensions of different rectangles : (15,1) (14,2) ..... you get 8 such rectangles.