Resposta :
[tex]\large\displaystyle\boxed{\begin{array}{l} \sf{obs : 5 \: d\acute{u}zias = 5 \cdot12 = 60 \:salgadinhos } \\ \\ \sf{a) \: \dfrac{2}{5} \cdot60 = 60 \div 5 \cdot2 = 12 \cdot2 =24=24\div12 = \boxed{ \boxed{ \sf{ 2\:d\acute{u}zias}}}} \\ \\ \sf{b) \: 60 - 24 = 36 = 36 \div 12 = \boxed{ \boxed{ \sf{3 \:d\acute{u}zias}}}}\end{array}}[/tex]
Vamos là.
total = 5 duzias
a)
2*5/5 = 2 duzias
b)
3*5/5 = 3 duzias