Let b be the number of blue ribbons and r be the number of red ribbon and w be the number of white ribbons
b= w - 1
r = w + 3
But,
b + w + r = 32
substitute b= w- 1 and r = w+ 3 into the equation
w- 1 + w + w+ 3 = 32
Re-arrange
w + w + w - 1 + 3 = 32
3w + 2 = 32
Subtract 2 from both-side of the equation
3w = 32 - 2
3w = 30
Divide both-side of the equation by 3
w = 10
Hence, there are 10 numbers of white ribbons
