Question

please help me friends.

Answer 1

$6.solution \\ 1.678 \times 1000000000 \\ = 1678000000 \\ 7.solution \\ 4.2 \times 100 = 420km {h}^{ - 1} \\ \frac{3360}{420}h = 0.08 \times {10}^{2} h \: or \: 8 \: hour$