Math New Drill (Level 1) : Patterns and Regularity Problem 1(3) OTSUMA-2014

I connected rectangular paper of 3 cm in height 8 cm in width 16 pieces with X cm width of overlapping. 

The area of the rectangle connected was 321 cm². 

Find X.

Answer

1.4 cm

Solution

321 / 3 = 107 cm 

8 ×16 - 107 = 21 cm 

21 / (16 - 1) =1.4 cm