I'm guessing the question is "how far does he have to walk to the store from where he is"
if he is walking home, then hmm
distance from store to school=1.8/2 since it is halfway, so 0.9 miles
he has walked 0.36 miles
so he needs to walk 0.90-0.36=0.54 miles
he needs to talk 0.54 miles to get to the store
