Answer: width = 60 yd
 and Length= 110 yd
Explanation:
 Step 1
Perimeter of rectangle field is given as  2 ( L+ b)
 Let the width be represented as x
'and length which is 50 yd longer than the width be 
 =x+ 50 
 such that the Perimeter with 340 yd can be expressed as
Perimeter = 2 ( L+ b) = 2L + 2B
Step 2---Solving
Perimeter = 2L + 2B
 340 = 2(X+ 50) + (2 x)
340 = 2X+ 100 + 2X
340=4X + 100
340-100=4X
240= 4X
 X= 240/4
X= 60
 Width = x = 60 yards
 ;Length = 50 + x= 50 + 60 = 110yards