It is given in the question that,

Distance travelled by bus = 15 km 268 m

= (15 + ) km

= 15 + 0.268 km

= 15.268 km

Distance walked in the evening = 7 km 7 m

= (7 + ) km

= 7 + 0.007 km

= 7.007 km

Also,

Distance travelled by foot = 500 m

= km

= 0.500 km

Therefore,

Total Distance = 15.268 + 7.007 + 0.500

Hence, total distance of school from her residence = 22.775 km