Answer:
23
Step-by-step explanation:
We have to fill in the following tree (upside down)
TRW=? TRP=? TBW=? TBP=? SRW=? SRP=? SBW=? SBP=?
TR=? TB=? SR=? SB=?
T=? S=?
Where TRW means TriangularRedWooden, SBP SquareBluePlastic and so on.
We are going to fill in the entrances (?) from bottom to top by using the data provided.
75 triangular tiles T=75, S=69 (there are 144 tiles)
TRW=? TRP=? TBW=? TBP=? SRW=? SRP=? SBW=? SBP=?
TR=? TB=? SR=? SB=?
T=75 S=69
38 red triangular tiles. TR=38 TB=37 (75-38)
TRW=? TRP=? TBW=? TBP=? SRW=? SRP=? SBW=? SBP=?
TR=38 TB=37 SR=? SB=?
T=75 S=69
69 red tiles. SR=31 (69-38) SB=38 (69-31)
TRW=? TRP=? TBW=? TBP=? SRW=? SRP=? SBW=? SBP=?
TR=38 TB=37 SR=31 SB=38
T=75 S=69
23 red wooden triangular tiles. TRW=23 TRP=15 (38-23)
TRW=23 TRP=15 TBW=? TBP=? SRW=? SRP=? SBW=? SBP=?
TR=38 TB=37 SR=31 SB=38
T=75 S=69
36 red wooden tiles. SRW=13 (36-23) SRP=18 (31-13)
TRW=23 TRP=15TBW=? TBP=? SRW=13 SRP=18 SBW=? SBP=?
TR=38 TB=37 SR=31 SB=37
T=75 S=69
40 triangular wooden tiles. TBW=17 (40-23) TBP=20 (37-17)
TRW=23 TRP=15 TBW=17 TBP=20 SRW=13 SRP=18 SBW=? SBP=?
TR=38 TB=37 SR=31 SB=38
T=75 S=69
68 wooden tiles. SBW=15 (68-23-17-13) SBP=23 (38-15)
TRW=23 TRP=15 TBW=17 TBP=20 SRW=13 SRP=18 SBW=15 SBP=23
TR=38 TB=37 SR=31 SB=37
T=75 S=69
<em>Our tree is filled up!
</em>
how many blue plastic square tiles are there?
SquareBluePlastic = SBP = 23
