Distance between city , D = 782 km.
Number of trips in a week , n = 5.
Total distance covered in a week , d = D × n = 782 × 5 = 3910 km.
Now, distance covered in six weeks is :
[tex]D'=d\times 6\\\\D'=3910\times 6\ km\\\\D'=23460\ km[/tex]
Therefore, her assumption of travelling 40,000 km in six week is wrong.
Hence, this is the required solution.