Answer:
length = 78 feet
width = 36 feet
Step-by-step explanation:
Using one variable and an expression, you can set up an equation equal to the perimeter to find the measure of each side:
width = 'w'
length = '42ft longer than it was wide' = w + 42
The general formula for the perimeter of a rectangle:
P = 2w + 2l
Plugging in the given values and variables:
228 = 2w + 2(w + 42)
Distribute: 228 = 2w + 2w + 84
Combine like terms: 144 = 4w
Divide and solve: 36 = w
w = 36 ft
l = 36 + 42 = 78 ft
Answer:
Speed of plane in still air: 490 mile/hour
speed of wind: 70 mile/hour
Step-by-step explanation:
still speed = x wind speed = w
with wind: speed = still + wind
(x+w) * 3 = 1680 ...a
against wind: speed = still - wind
(x-w) * 4 = 1680 ...b
b-a ... 4x-4w-3x-3w = 0
x-7w = 0
x = 7w
substitution: (7w+w)*3 = 1680 8w = 560 wind speed (w) = 70
still speed (x) = 7w = 490 mile/hour
Answer:
y is less than or equal to -12
y<=-12
Step-by-step explanation:
There are 14 nickels and 7 dimes.
(You can check by multiplying 14 by 5 for nickels and 7 times 10 for dimes. This would add up to 1.35)