On a road map that uses a scale of 1inch: 20 miles, two cities are 7 inches apart. if you are making a map that uses a scale of 3inches: 35 miles, how far apart are the same two cities on your map?

Well, we know that there are 2 cities. The original map is having 1 inch represent 20 miles. The cities are 7 inches apart. First off, you need to know how far apart in MILES they are.

20*7=140, so the cities are 7 inches apart, or 140 miles.

So, you want to make an identical map, but you want your measurements to be a bit more spaced. we know YOUR map will have every 3 inches representing 35 miles, but we need to know how far apart in inches will 140 miles be.
Well, we simply take 140 and divide it by 35 then!
140/35=4
Wait, your not done yet, The 4 only represents how many "35 mile" increments you need to get to 140. This means the number representing inches also has to be multiplied by this 4 to get your final answer.
3*4=12
This means on YOUR map, the 2 cities will be 12 inches apart.

~Hope this helps!