Bonjour,
A = [tex]\frac{20}{28}+\frac{3}{14}[/tex][tex]X \frac{4}{9}[/tex]
A = [tex]\frac{20}{28}+\frac{12}{126}[/tex]
A = [tex]\frac{20X9}{28X9} +\frac{12X2}{126X2}[/tex]
A = [tex]\frac{180}{252}+\frac{24}{252}[/tex]
A = [tex]\frac{204}{252}[/tex]
A = [tex]\frac{204/12}{252/12}[/tex]
A = [tex]\frac{17}{21}[/tex]