To understand the problem, let's first draw a free body diagram of the forces exerted by Judy and Ike on the truck. (Refer to the left side of the attachment).
To solve for the resultant, we just use the tip-to-tail method. This is illustrated on the right side of the attachment.
We can see that the tip-to-tail method forms a right triangle thus we can just apply the Pythagorean theorem in solving for Ike's force.



ANSWER: Ike must pull the truck with a force of 16.0 N.
B)Emily either switched the signs for no reason or solved it in the incorrect order
C) The sudent solved the equation in an incorrect order. Emily solved the first, then third, then second, which was the incorrect order. Edgar solved the thirst root, then second, then third, thus he is correct.
D is correct for this problem