Question 176860
Use simultaneous equations to solve, doing the following:

Let speed of plane be p
Let speed of ship be s

Therefore,        4p   +       25s   =   1,580 ---------  (i) x 1
And, .5(4p) + 1.25(25s) = 1,315,  or  2p  +  31.25s = 1,315 ---------  (ii) x -2
			     4p    +       25s   =   1,580 --------- (iii)
			    -4p    -    62.5s   =   -2,630 --------- (iv)
			              -   37.5s   =     - 1,050
				             s   =   28

Substituting 28 for s in eq. (i), we get:	  4p   +    700	  =   1,580	
							       4p   =   880
							         p   =   220
Speed of plane is 220 mph, and speed of ship is 28 mph.