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.
<span>Brenda would be correct, another way to find the answer would be to use the keep change flip method. Where you keep 5/2 change division to multiplication then flip 4/1.
The equation would then be 5/2 * 4/1 then you just multiply straight across 5*4 = 20 and 2*1 equals 2. You end up with 20/2 which reduces to 10</span>
Answer:
$2.52/12= $.21
the cost of one can of soda is $.21
Step-by-step explanation:
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top left
Step-by-step explanation:
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the fourth answer, hope this can help
