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:
C
Step-by-step explanation:
Number 4
Answer:
376 inches^2
Step-by-step explanation:
<h3>1. Divide up each type of rectangle </h3>
- 10x6
- 6x8
- 8x10
<h3>2. Find the area of each rectangle</h3>
- 10x6=60
- 6x8=48
- 8x10=80
<h3>3. Multiply each rectangle by two to get the opposite one</h3>
- 60x2=120
- 48x2=96
- 80x2=160
<h3>4. Add them together</h3>
120+96+160=376
The surface area is 376 inches^2
The second option ! 2.54 - 2.3 = 0.24
One decade is 10 years+ 8 years is 18 total years
18 minus 9 is 9 years
Hope this helps