Step-by-step explanation:
Let x be the length and y be the width of the rectangular plot.
The plot is bounded on one side by a river and on the other three sides by a single-strand electric fence. It means,
x+2y = 1500
x = 1500 - 2y ....(1)
We know that the area of a rectangular plot is given by :
A = xy ....(2)
Put the value of x from equation (1) in (2)
.....(3)
For largest area, differentiate above area equation wrt y.
Put the value of y in equation (1).
x = 1500-2(375)
= 750 m
Put the value of y in equation (3).
Hence, the largest area is 281250 m² and its dimensions are 750 m and 375 m.