The total distance that the family has driven is the sum of the distances from Phoenix to San Francisco,
d = sqrt ((5 - -16)² + (-36 - -12)²) = 10.63
from San Francisco to Blythe,
d = sqrt ((-9 - 5)² + (-20 - -36)²) = 21.26
from Blythe to Los Angeles,
d = sqrt ((-4 - -9)² + (-33 - - 20)²) = 5.83
Adding the distances, we get 37.72.
(-4, 2), (-1, 2), and (-4, 0
75kg should be the answer