The least-square regression line has a slope of:
m=(nΣxy-ΣyΣx)/(nΣx²-ΣxΣx)
and a y-intercept of:
b=(Σy-mΣx)/n
In this case: n=7, Σxy=4899, Σy=391, Σx=85, Σx²=1153 so
m=(7(4899)-391*85)/(7(1153)-85*85))=1058/846
b=(391*846-85*1058)/(7*846)=34408/846
So the line of best fit is:
y=(1058x+34408)/846 and if we approximated this as your answers see to have done....
y=1.25x+40.67
Can you post a picture please!
Time out = d/so = d/523
time back = d/sb = d/415
t = time out + time back
11 = d/523 + d/415 find common deneminator
11 = (415d + 523d)/(523*415)
11*523*415 = 415d + 523d
2387495 = 938d
d = 2545 miles
hope this help
This problem is related to the concept composite function
