Answer:
speed of plane = 157.5 mph
speed o wind = 17.5 mph
Step-by-step explanation:
Distance traveled to move from one position to other is given as
![d = 700 miles](https://img.qammunity.org/2020/formulas/physics/high-school/1lytobkv20qn7b78i2jhwcqylfhkng4wg5.png)
time taken by it
![t = 4 hr](https://img.qammunity.org/2020/formulas/physics/high-school/mx87iutxwyojd9r83hkrw1cau37t6uhv2i.png)
so here the speed is given as
![v_p + v_w = (700)/(4)](https://img.qammunity.org/2020/formulas/physics/high-school/sxonouny8mrf406zyr0eezt86gqh1567ql.png)
![v_p + v_w = 175 mph](https://img.qammunity.org/2020/formulas/physics/high-school/o2wd8idanz334fx0l7i4qhhq64to6svd4w.png)
during his return journey we have
![v_p - v_w = (700)/(5)](https://img.qammunity.org/2020/formulas/physics/high-school/7uhaw4ts6tjnwdsit5n08q7kkpikqsk7mi.png)
![v_p - v_w = 140 mph](https://img.qammunity.org/2020/formulas/physics/high-school/9rm7k7q8btyepnsmfph06auwz4gfpwol1a.png)
now from above two equations we have
![v_p = 157.5 mph](https://img.qammunity.org/2020/formulas/physics/high-school/kfq63eicus9ue1qrntvb2ek0v7658az1vg.png)
![v_w = 17.5 mph](https://img.qammunity.org/2020/formulas/physics/high-school/m001j3wbajxpw07ko8jsi9d4j2fp8vtk5n.png)