Alexandra lives thirtythree miles from work During the summe

Alexandra lives thirty-three miles from work. During the summer, she rides her bike at seven mph to the metro station. She then takes the metro to work, which travels at thirty-nine mph. If she spends twenty-one minutes (which is .35 hour) less on the bike than on the metro, what is the distance from her house to the metro? (Work with the time in hours and round the final answer to a whole number.)

Solution

total distance = 33miles
Bike\'s speed = 7mph.
Metro\'s speed = 39mph.
Bike\'s time = x-0.35hours
Metro\'s time = x

7(x-0.35)+39(x)=33
7x-2.45+39x=33
46x=35.45
x=0.77

Metro--->39(0.77)
39(0.77)
30 (rounded)

Hence, the distance from home to the station is 30 miles.