5. Calculează
a)
[tex]\frac{1}{12} \times \frac{3}{4} \times \frac{16}{25} + \frac{1}{15} \times \frac{33}{4} \times \frac{28}{55} [/tex]
b)
[tex] \frac{1}{12} \times \frac{1}{5 } + \frac{1} {12} \times \frac{7} {10} + \frac{1}{12} \times \frac{1}{15} [/tex]
​