[tex]p\%=\dfrac{p}{100}\\\\40\%=\dfrac{40}{100}=\dfrac{4}{10}=0.4;\ 60\%=\dfrac{60}{100}=\dfrac{6}{10}=0.6;\ 55\%=\dfrac{55}{100}=0.55\\\\\left\{\begin{array}{ccc}x+y=5&\to x=5-y\\0.4x+0.6y=0.55\cdot5\end{array}\right\\\\\text{Use substitution method}\\\\0.4(5-y)+0.6y=2.75\qquad\text{use distributive property}\\\\(0.4)(5)+(0.4)(-y)+0.6y=2.75\\\\2-0.4y+0.6y=2.75\qquad\text{subtract 2 from both sides}\\\\0.2y=0.75\qquad\text{multiply both sides by 5}\\\\\boxed{y=3.75}[/tex]
[tex]\text{Put the value of y to the first equation}\\\\x=5-3.75\\\\\boxed{x=1.25}\\\\Answer:\ x=1.25\ and\ y=3.75.[/tex]