Problem
First name
Ewan Robertson
School
Wilson's School
Country
Age
14
Triangle = a
Square = b
Hexagon = c
Circle = d
3d + a =18
3d + b = 20
b = a + 2
2a + 2b = 28
2a + 2(a + 2) = 28
2a + 2a + 4 = 28
4a = 24
a = 6
3d + a = 18
3d + 6 = 18
3d = 12
d = 4
3(4) + b = 20
12 + b = 20
b = 8
2b + 2c = 30
2(8) + 2c = 30
16 + 2c = 30
2c = 14
c = 7
a + c + 2d = x
6 + 7 + 2(4) = x
6 + 7 + 8 = x
21 = x
? = 21