Given :
The length of Dwight's garden is 12.5 meters.
Dwight measured it but made a measurement error of 6%.
To Find :
The lowest and highest measurement Dwight could have made.
Solution :
Error in length measuring is :

Therefore, the lowest and highest measurement he could have is 12.5 - 0.75 = 11.75 meters and 12.5 + 0.75 = 13.25 meters.