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:
B. 1,440
Step-by-step explanation:
2.75 hours.
The equation would be 32x + 46 = 134. So we subtract 46 from 134 and get 88. Now we have to divide that by 32 to get the total of 2.75 hours
<h3>Answer</h3><h3>{EQUATION}</h3>
- An equation is any statement that has an equal sign or its equivalent. Word such as equal, is, are, were, was, is is equal to, and result is can be used in place of the <u>(</u><u>=</u><u>)</u> symbols.
