Charlotte spent her morning in downtown. After a delicious cup of hot chocolate at location #102, she visited a perfume salon at location #56 across the street. She then stepped into a clothing boutique at location #305. She crossed the street once again and finished her shopping tour in a toy shop at location #73.
How many streets Charlotte changed during her morning shopping spree provided she visited each location from the front entrance?
Every street has even numbers on one side and odd ones on another. The #56 was across the street from #102. Both are even, thus should be on different streets – Streets A and B respectively. Between #56 and #305 Charlotte didn’t cross the street. Since the locations are even and odd respectively and no crossing of the street had been made, the only way for Charlotte to change to the odd number was to make a turn around the corner, changing the street in that way – Street C. Between #305 and #73 a crossing was performed. Since the crossing didn’t change the odd-even alteration, the #73 was on another street – Street D. In total Charlotte changed four streets.