Answer :
Notice that 2*3=6.
On the other hand, according to the question, 3 girls can decorate a total of
[tex]\begin{gathered} \frac{60}{1.5}=40 \\ \Rightarrow40\cdot2=80 \end{gathered}[/tex]80 holiday cards in one hour. Therefore, 6 girls can decorate 2*80=160 holiday cards in the same amount of time.
The answer is 160 holiday cards per hour