<span>Since one standard deviation is 20 luggages, 3 standard deviations above the mean is 3*20=60 luggages above the mean of 380 luggages, so 60+380 gives the answer C, 440.</span>
Answer:
Step-by-step explanation:
rate = d / t
rate = 192 / 3
rate = 64 miles / hour
Now you want to know how long it can take to get 448 miles
d = r * t
t = d / r
t = 448/64
t = 7 hours.
You could actually do it using proportions.
192/3 = 448/x Cross multiply
192*x = 448*3
192*x = 1344 Divide by 192
x = 1344/192
x = 7
Do this the way you feel is the best way.
Answer:
x=5, y=2
Step-by-step explanation:
You simply write down what you see:
3x - 4y + 4x - 5y = 17
2x - 3y + 3x - 5y = 9
Then you simplify by grouping the x and the y terms:
7x - 9y = 17
5x - 8y = 9
Now you want to get equal amounts of x or y. Let's go for x. If we multiply the top eq with 5 and the bottom one with -7, we get:
35x - 45y = 85
-35x + 56y = -63
-------------------------+ now we can add them:
11y = 22 divide by -11
y = 2
So 7x - 18 = 17, x =5
Finally, it makes sense to double check by filling in these answers in the original equations, just to see if no mistakes were made:
3*5 - 4*2 = 7
4*5 - 5*2 = 10
7+10 = 17: ok!
2*5 - 3*2 = 4
3*5 - 5*2 = 5
4+5 = 9: ok!
7x+8(x+1/4) = 3(6x-9)-8
7x+8x+2 = 18x - 27 -24
15x + 2 = 18x - 51
+51 + 51
15x + 53 = 18x
-15x = -15x
53 = 3x
17.66 = x
Answer:
C) 273 ft²
Step-by-step explanation:
7x11x3=231
2x1/2x7x6=42
231+42=273