Question

quantos segundos tem 0,3 horas ?

Answer 1

$1\text{ min}=60\text{ s}\\ \\ \\ 1\text{ hora}=60\text{ min}\\ \\ 1\text{ hora}=60\times \left(60 \text{ s}\right )\\ \\ 1\text{ hora}=3600\text{ s}$


Logo

$0,3\text{ hora}=0,3 \times \left(3600\text{ s} \right)\\ \\ \boxed{0,3\text{ hora}=1\,080\text{ s}}$