22. The diagram shows a plan of a town with various bus stops.
There are four bus routes in the town.
Route 1 goes $\mathrm{C}-\mathrm{D}-\mathrm{E}-\mathrm{F}-\mathrm{G}-\mathrm{H}-\mathrm{C}$ and is $17 \mathrm{~km}$ long.
Route 2 goes $\mathrm{A}-\mathrm{B}-\mathrm{C}-\mathrm{F}-\mathrm{G}-\mathrm{H}-\mathrm{A}$ and is $12 \mathrm{~km}$ long.
Route 3 goes $\mathrm{A}-\mathrm{B}-\mathrm{C}-\mathrm{D}-\mathrm{E}-\mathrm{F}-\mathrm{G}-\mathrm{H}-\mathrm{A}$ and is $20 \mathrm{~km}$ long.
Route 4 goes $\mathrm{C}-\mathrm{F}-\mathrm{G}-\mathrm{H}-\mathrm{C}$.
How long is route 4 ?

A $10 \mathrm{~km}$
B $9 \mathrm{~km}$
C $8 \mathrm{~km}$
D $7 \mathrm{~km}$
E $6 \mathrm{~km}$
22. B The roads covered in routes 1 and 2 combined are the same as the roads covered in routes 3 and 4 combined. Therefore the length of route 4 is $(17+12-20) \mathrm{km}=9 \mathrm{~km}$.