Can someone help me to answer this question, please and explain it.

This is calculus 1

3. An airline policy states that all baggage must be box-shaped with a sum of the length, width, and height not exceeding 120 Inches. a) (12 pts) If the length of the base of the box is twice the width, what are the dimensions and volume of a box with the greatest volume under these conditions? Justify your answer using either the First Derivative Test or the Second derivative Test. Let x = width of the base of the of the box and h = height of the box X= h= Volume = b) (3pts) Justification: (circle which you are using): 1"t Der Test 2nd Der Test