Question 1179938

Justin can run 10 km in the same amount of time that Leo can run 12 km. If Leo can run 1 kph faster than Justin, how fast can Leo run?
<pre>Let Leo's speed be S
Then Justin's is: S - 1
We then get the following TIME equation: {{{matrix(1,3, 12/S, "=", 10/(S - 1))}}}
{{{matrix(1,3, 6/S, "=", 5/(S - 1))}}} ----- Factoring out GCF, 2, in NUMERATORS
5S = 6S - 6 ----- Cross-multiplying
5S - 6S = - 6
- S = - 6
Leo's speed, or {{{highlight_green(matrix(1,6, S, "=", (- 6)/(- 1), "=", 6, "km/h"))}}}