[tex]\frac{17}{28}[/tex] of all the letters are Xs.
What is ratio?
'A ratio can be defined as the relationship or comparison between two numbers of the same unit to check how bigger is one number than the other one.'
According to the given problem,
Ratio of red letters to blue letters = 2 : 5
Ratio of red Xs to red Ys = 1 : 3
Ratio of blue Xs to blue Ys = 3 : 1
Number of red letters = [tex]\frac{2}{2+5}[/tex]
= [tex]\frac{2}{7}[/tex]
Number of Xs = [tex]( \frac{2}{7} * \frac{1}{1+3}) + [( 1-\frac{2}{7})*\frac{3}{3+1})][/tex]
= [tex](\frac{2}{7} *\frac{1}{4})+(\frac{5}{7}*\frac{3}{4} )[/tex]
= [tex]\frac{1}{4}+\frac{15}{28}[/tex]
= [tex]\frac{2+15}{28}[/tex]
= [tex]\frac{17}{28}[/tex]
Hence, we can conclude, [tex]\frac{17}{28}[/tex] of all letters are Xs.
Learn more about ratio here: https://brainly.com/question/13419413
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