Answer:
4.125 hours
Step-by-step explanation:
Trapezoid shaped lawn :
Bases : 90 ; 126 ; height = 90
Area of trapezium = 1/2(a+b) h ; a and B are the bases and h = height
Area of trapezium = 1/2(90 + 126) * 75
Area = 108 * 90 = 8100 feets
Triangular lawn :
Height = 80 feets ; Base = 105 feets
Area of triangle = 1/2 base * height
Area = 1/2 * 80 * 105 = 4200 feets
Rectangular lawn :
Length = 120 feets ; width = 90 feets
Area of rectangle = Length * width
Area = 120 * 90 = 10800 feet²
Area of all 3 lawns = (8100 + 4200 + 10800) = 23100
In 2 hours ; Herbert can now (160 * 70) = 11200 feets
23100 / 11200 = 2.0625
Tine required to mow all three lawns :
2 hours * 2.0625 = 4.125 hours
= 4 hours, 7 minutes, 30 seconds
