Answer:
648
Step-by-step explanation:
Running this in Python, with the code as follows,
import math
cur_numbers = [0] * 3
num = 0
for i in range(100, 1000):
cur_numbers[2] = i % 10
i = math.floor(i/10)
cur_numbers[1] = i % 10
i = math.floor(i/10)
cur_numbers[0] = i % 10
if(len(set(cur_numbers)) == 3):
num += 1
print(cur_numbers)
print(num), we get 648 as our answer.
Another way to solve this is as follows:
There are 9 possibilities for the hundreds digit (1-9). Then, there are 10 possibilities for the tens digit, but we subtract 1 because it can't be the 1 same digit as the hundreds digit. For the ones digit, there are 10 possibilities, but we subtract 1 because it can't be the same as the hundreds digit and another 1 because it can't be the same as the tens digit. Multiplying these out, we have
9 possibilities for the hundreds digit x 9 possibilities for the tens digit x 8 possibilities for the ones digit = 648
Answer:
There's no direct variation
Step-by-step explanation:
Required
Determine if there's a direct variation between the number and its position
I'll start by giving an illustration of how the triangle is represented using stars (*)
*
**
***
****
*****
Represent the line number with y and it's position with x
On line 1:
y = 1, x = 1
On line 2:
y = 2, x = 3
On line 3:
y = 3, x = 6
On line 4:
y = 4, x = 10
On line 5:
y = 5, x = 15
Note that, x is gotten by calculating the accumulated number of stars while y is the line number.
Direct variation is represented by
y = kx
Or
kx = y
Where k is the constant of variation
For line 1:
Substitute 1 for y and 1 for x
k * 1 = 1
k = 1
For line 2:
Substitute 2 for y and 3 for x
k * 3 = 2
Divide through by 3
k = ⅔
Note that the values of k in both computations differ.
This implies that there's no direct variation and there's no need to check further.
Answer:
a. 144 ft
b. 5 s
Step-by-step explanation:
h = -16t² + 64t + 80
a. This is a parabola, so the maximum height is at the vertex.
t = -64 / (2 × -16)
t = 2
h = -16(2)² + 64(2) + 80
h = 144
The apple reaches a maximum height of 144 ft.
b. 0 = -16t² + 64t + 80
0 = t² − 4t − 5
0 = (t + 1) (t − 5)
t = -1 or 5
t must be positive, so it takes 5 seconds to reach the ground.
Answer:
2x² - 9x - 5
Step-by-step explanation:
Step 1: FOIL
2x² - 10x + x - 5
Step 2: Combine like terms
2x² - 9x - 5
Y = -2x + 3
Hope that helps.
