Plotting Latitude & Longitude Lines

Chapter 4, Homework question 3a from ASA's Coastal Navigation & Piloting textbook: Plotting latitude and longitude lines on a navigation chart.

[@simonhantler8062]

where did you get .05 nm from.arent they in 10th of a mile so two would be 2/10ths?

[@mdschoolofsailing]

.05 is half of a tenth