Answer:
27/14
Step-by-step explanation:
to divide by a fraction flip the fraction over and multiply
3/7 divided by 2/9
flip 2/9
3/7 times 9/2
just multiply the top and bottoms by each other
27/14
Let the three gp be a, ar and ar^2
a + ar + ar^2 = 21 => a(1 + r + r^2) = 21 . . . (1)
a^2 + a^2r^2 + a^2r^4 = 189 => a^2(1 + r^2 + r^4) = 189 . . . (2)
squaring (1) gives
a^2(1 + r + r^2)^2 = 441 . . . (3)
(3) ÷ (2) => (1 + r + r^2)^2 / (1 + r^2 + r^4) = 441/189 = 7/3
3(1 + r + r^2)^2 = 7(1 + r^2 + r^4)
3(r^4 + 2r^3 + 3r^2 + 2r + 1) = 7(1 + r^2 + r^4)
3r^4 + 6r^3 + 9r^2 + 6r + 3 = 7 + 7r^2 + 7r^4
4r^4 - 6r^3 - 2r^2 - 6r + 4 = 0
r = 1/2 or r = 2
From (1), a = 21/(1 + r + r^2)
When r = 2:
a = 21/(1 + 2 + 4) = 21/7 = 3
Therefore, the numbers are 3, 6 and 12.
Answer:
42 ft in 6 seconds
Step-by-step explanation:
The person whom walks a greater distance in lees time is faster
(27 mi/hr) x (1 hr / 60 min) = (27/60) (mi/min) = 0.45 mile/minute
Using the same kind of calculation, we can see
that the world record times for other distances
correspond to:
200 meters 23.31 mph
400 meters 20.72 mph
800 meters 17.73 mph
1000 meters 16.95 mph
1500 meters 16.29 mph
1 mile (1,609 meters) 16.13 mph
2,000 meters 15.71 mph
10,000 meters 14.18 mph
30,000 meters 12.89 mph
Marathon (42,195 meters) 13.10 mph
Except for that one figure at the end, for the marathon,
which I can't explain yet and I'll need to investigate further,
it's pretty obvious that a human being, whether running for
his life or for a gold medal, can't keep up the pace indefinitely.
If you would like to calculate 6/(x+1)-5/2=6/(3x+3), you can do this using the following steps:
6/(x+1)-5/2=6/(3x+3)
6/(x+1)-5/2=6/(3(x+1)) /*(x+1)
6 - 5/2 * (x+1) = 6/3
6 - 2 = 5/2 * (x+1)
4 = 5/2 * (x+1) /*2/5
4 * 2/5 = x + 1
8/5 - 1 = x
x = 8/5 - 5/5 = 3/5
The correct result would be 3/5.
