Mark starts a rock climb when he is 1 mile above sea level. He can climb at the rate of 1.5 miles per hour. Which of the following functions would express Mark's height above sea level over time?

f(x) = 1.5x
f(x) = 1 + 1.5x
f(x) = 2.5x

Question

Mark starts a rock climb when he is 1 mile above sea level. He can climb at the rate of 1.5 miles per hour. Which of the following functions would express Mark's height above sea level over time? 



f(x) = 1.5x
f(x) = 1 + 1.5x
f(x) = 2.5x

eujc21 · Answer

$$ y = mx+b$$ where $$y = f(x)$$ and $$m = slope$$ which is the rate of the function. Mark is already at $$b =1$$ which is 1 up on the slope. Try plugging in 0 for x and you get y =1 the one mile he is above sea level.