Question

The library is 3 miles east of the city hall. The mall is 10 miles west of the library. How far and in what direction is the mall from the city hall?

Answer 1

7 miles west of the city hall

Explanation:

The city hall on a coordinate plane is at the origin (0, 0). That means that if the library is 3 miles straight east, its coordinates are (3, 0). If the mall is 10 miles straight west of the library, we find its coordinates by subtracting 10 from 3, which puts us at the coordinate (-7, 0). That means that the mall is 7 miles west of the city hall.

Answer 2

`\boxed{\text{seven miles west}}`

Explanation:

Think of this as a number line in which city hall is at 0.

East of city hall is the positive direction and west is negative.

Start at city hall and go three miles east to the library. You are at +3.

Then go 10 mi west to the mall. You end up at -7.

+3 – 10 = -7

`\text{The mall is \boxed{\textbf{seven miles west}} of city hall.}`