Van is travelling
[tex]64\frac{7}{8}\text{ miles per hour}[/tex]
That is,
[tex]68\frac{7}{8}=\frac{551}{8}[/tex]
The aeroplane is
[tex]5\frac{6}{7}=\frac{41}{7}[/tex]
times faster than van.
Therefore, aeroplane is travelling,
[tex]\frac{551}{8}\times\frac{41}{7}=\frac{22591}{56}[/tex]
That is aeroplane is travelling
[tex]403\frac{23}{56}\text{ miles per hour}[/tex]
