Answer:

Explanation:
From the question we are told that:
Number of turns 

Conductor each with side length 
Current 
Magnetic field
Generally the equation for the total magnetic moment M is mathematically given by



The load is the weight of the rock that Jonathan lifts:

The effort instead is the force applied in input to the lever in order to lift the rock:

So, the ratio between load and effort for this exercise is

So, the ratio is 10:1.