8 cm
1 answer:
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Answer:
Part A
The width of the garden is approximately 3.987 meters
Part B
Please find attached the drawing of the solution
Step-by-step explanation:
Part A
The given parameters are;
The dimensions of the backyard of the home = 25 m by 30 m
The width of the garden to be built in the yard = Uniform width
The shape of the grass left inside = Rectangular
The area of the grass at the center = The area of the garden
Let 'x' represent the width of the garden, we have;
The length of the rectangular grass area at the center, l = 30 - 2·x
The width of the rectangular area of grass at the center, w = 25 - 2·x
The area of the rectangular backyard, A = 30 m × 25 m = 750 m²
The area of the rectangular backyard, A = (The area of the garden) + (The area of the rectangle of grass inside)
The area of the rectangle of grass, GA = (30 - 2·x)·(25 - 2·x) = The area of the garden
The area of the rectangular backyard, A = 750 = (30 - 2·x)·(25 - 2·x) + (30 - 2·x)·(25 - 2·x) = 2 × (30 - 2·x)·(25 - 2·x) = 8·x² - 220·x + 1,500
∴ 750 = 8·x² - 220·x + 1,500
8·x² - 220·x + 1,500 - 750 = 0
8·x² - 220·x + 750 = 0
x = (220 ± √(220² - 4 × 8 × 750))/(2 × 8)
x ≈ 23.513, or x = 3.987
When x = 25.513, the width of the rectangle of grass inside, w = 25 - 2 × 23.513 = -22.026, which is not a natural (physically possible)
Therefore, the possible width of the garden, x ≈ 3.987
Part B
The drawing of the solution created with MS Visio is attached
Average speed =
Ishan's Speed uphill = 10mph
Time taken = 18 minutes = 18/60 = 3/10 hours
Now distance = rate × time
Distance traveled by Ishaan up hill = 10 × 3/10 = 3 miles
Now returning back home
Distance = 3 miles
Rate = 30 mph
So time taken = distance/ rate = 3/30= 1/10 hours = 1/10 ×60 = 6 minutes.
Now total distance traveled = 3 + 3 = 6 miles
Total time taken = 18 + 6 = 24 minutes = 24/60 = 2/5 hours
Average speed
=
= 15 mph
Ishaan's average speed for the entire trip from home to the gift store and back is 15mph