Question

Peter organizes morning hikes for his friends every Saturday. When the hiking trail is 3 km long, 19 friends join him and when the trail is 5 km long, only 7 friends tag along. There exists a linear relationship between the distance of the hiking trail (in km) and the number of friends who tag along. The number of friends depend on the distance of the trail. Determine how many friends will tag along to a hiking trail of 2 km. ​

Answer 1

25

Explanation:

x = distance of the hike

y = number of friends coming along

so, we are looking for a linear relationship between these two.

y = ax + b

we need to find the factor a and the constant offset b.

19 = a×3 + b

7 = a×5 + b

7 - b = a×5

a = (7-b)/5

19 = (7-b)×3/5 + b

19 = (21 - 3b)/5 + b

95 = 21 - 3b + 5b

74 = 2b

b = 37

a= (7-37)/5 = -30/5 = -6

so, the relationship is

y = -6x + 37

for 2km hiking

y = -6×2 + 37 = -12 + 37 = 25 friends