It is given in the question that Maria hiked 1.75km up to Mt Washington . Then back down 800 meters= 0.8km to meet her friend . So she is at
up to Mt Washington .
Then she back up by 910 m = 0.91 km. So she is at
up Mt Washington .
And Mt Washington is 1917 m = 1.917 km tall .
So she have to go up by
