Answer:
18x - 3
Step-by-step explanation:
Add all the X values
8x + -2x + 12x = 18x
Put the final numbers on the side.
-3
18x-3
A) The first step needs 100 bricks, the second needs 98, the third needs 96, and so on. Therefore the number of bricks for the nth step is: a_n = a_1 + d(n-1), where a_1 = 100 (the first term), d = -2 (difference).
a_n = 100 - 2(n-1) = 102 - 2n, and for the 30th step, a_30 = 102 - 2*30 = 42. So the top step will need 42 bricks.
b) The total staircase will need: 100 + 98 + 96 + ... + 44 + 42, and there are n = 30 terms. Using the formula for the sum of an arithmetic sequence:
S = (a_1 + a_n)*n/2 = (100 + 42)*30/2 = 2130
Therefore, 2130 bricks are required to build the entire staircase.
Answer:
$54.37
Step-by-step explanation:
First, need to find 15% of 47.28.
47.28 x .15 = 7.092
Then we add that to the original cost.
47.28+7.092 = 54.372
Round your answer
$54.37
Hope this helped!
