A student walks and jogs to college each day. The student averages 5 km/h walking and 9 km/h jogging. The distance from home to college is 8 km, and the student makes the trip in 1 hour. How far does the student jog?

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Answer 1 · 2016-02-07T05:31:09

6.75 km

Let $x$ be the duration spent jogging.

Since the total travel duration is 1 hour, $1 - x$ is the duration spent walking

$d = st$

The distance covered by jogging is

$=> d_j = 9x$

Meanwhile, the distance covered by walking is

$d_w = 5(1 - x)$

Since the total distance covered is 8 km, we have

$=> 9x + 5(1 - x) = 8$

$=> 9x + 5 - 5x = 8$

$=> 4x = 3$

$=> x = 3/4$

We want the distance covered by jogging,

$d_j = 9x$

$d_j = 9(3/4)$

$d_j = 27/4 = 6 3/4 = 6.75$