Hello!
The ratio of 1:5
The ratio we are find is 3 : x
We have to find what happened between the ratios
To do this you divide the new number by the old one
3 / 1 = 3
They multiplied the scale by 3 to get the actual wall
Use this to get the length of the wall
3 * 5 = 15
The answer is 15 inches or 1ft 3in
Hope this helps!