If the average rates were 20 and 25 miles per hour, then together they cover 45 miles of the distance they are separated by per hour. The ships will be 30 miles apart when 270 miles have been covered, so it takes 270/45=6 hours to cover the distance. 6 hours after 5 PM is 11:00 PM.
I would think that all but one point would be on the line. One way to approach this problem is to find the equation of the line based upon any two points chosen at random, and then determine whether or not the other points satisfy this equation. Next time, would you please enclose the coordinates of each point inside parentheses: (2.5,14), (2.25,12), and so on, to avoid confusion.
14-12
slope of line thru 1st 2 points is m = ---------------- = 2/0.25 = 8
2.50-2.25
What is the eqn of the line: y = mx + b becomes
14 = (8)(2.5) + b; find b:
14-20 = b = -6. Then, y = 8x - 6.
Now determine whether (12,1.25) lies on this line.
Is 1.25 = 8(12) - 6? Is 1.25 = 90? No. So, unless I've made arithmetic mistakes, (1.25, 5) does not lie on the line thru (2.5,14) and (2.25,12).
Why not work this problem out yourself using my approach as a guide?
Answer:
J
Step-by-step explanation:
If you were to plug in your variables, you would see that -6, and -7 is over 25 and the rest of your variables aren't. So, therefore your answer is J.
Nickels = x
dimes = x + 4
quarters = x
Value of coins:
nickel = 5 cents
dime = 10 cents
quarter = 25 cents
5x + 10(x + 4) + 25x = 3.20
5x + 10x + 40 + 25x = 320
40x = 320 - 40
40x = 280
x = 280/40
x = 7
There are 7 quarters, 7 nickels and 11 dimes.
Plug it in
7(4) + 8(5) which would be 28 + 40
Answer: 68
