Final answer:
The ratio of eggs in three boxes to the total number of eggs is 1:5.
Step-by-step explanation:
To find the ratio of the number of eggs in three boxes to the total number of eggs, we need to first determine the total number of eggs. The farmer has 15 boxes, and each box contains 6 eggs, so the total number of eggs is 15 x 6 = 90 eggs.
Now, to find the number of eggs in three boxes, we multiply the number of boxes (3) by the number of eggs in each box (6), which gives us 3 x 6 = 18 eggs.
The ratio of the number of eggs in three boxes to the total number of eggs is therefore 18:90, which can be simplified to 1:5.