Wednesday, 20 October 2010

3 & 4 Legged Tables

Question

Several three-legged tables and four-legged table have a total of 23 legs. If there is more than one table of each type, what is the number of three-legged tables?
A) 6
B) 7
C) 3
D) 4
E)  5




Answer
The simplest way of doing this is by writing out the number of legs in a table (shown below)

Tables
‘3 Legged’ Tables
‘4 Legged’ Tables
To Make 23
1
3
4

2
6
8
15
3
9
12
11 (not a multi. of 3)
4
12
16
7 (not a multi. of 3)
5
15
20

6
18
24

7
21


8
24



As shown above:
  • 8 legs are allowed '4 legged table'
  • 15 legs are allowed '3 legged table'
So: 5 = 3 'legged table'
       2 = 4 'legged table'   


E = 5
                                                                                                             

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