Let's find all the possible addition solutions for 24.
0,24
1,23
2,22
3,21
4,20
5,19
6,18
7,17
8,16
9,15
10,14
11,13
12,12
Now we multiply these until one of them equals 143
0*24=0
1*23=23
2*22=44
3*21=63
4*20=80
5*19=95
6*18=108
7*17=119
8*16=128
9*15=135
10*14=140
11*13=143
Since 11*13=143, then 11 and 13 are the width and length
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