There’s two ways to substitute, but i think you mean if you know x but don’t know y. if that is true, then yes use substitution
Zoe will have to run 11.9 miles
Given that Zoe's average running speed is about 6 4/5 miles per hour, this is expressed as:
In order to determine the distance he can run in 1 3/4 hour, we can write;
Cross multiply to have:
x * 1 = 7/4 * 34/5
x = 238/20
X = 11.9miles
Hence Zoe will have to run 11.9 miles
Learn more on speed here: brainly.com/question/3004254
