Jordan is starting to save $150 to buy a new cell phone. In December, he saved $5. In January, he plans twice as much as he did
1 answer:
9514 1404 393
Answer:
April
Step-by-step explanation:
The sequence of amounts saved is a geometric sequence. The sum of those amounts is given by the formula ...
Sn = a1·(r^n -1)/(r -1)
where a1 is the amount saved in month 1, r is the common ratio, and n is the number of months. We want to find n such that ...
150 ≤ 5(2^n -1)/(2 -1)
30 ≤ 2^n -1
31 ≤ 2^n
We can solve this using logarithms, or we can make use of our knowledge of powers of 2: 2^5 = 32. That is, n = 5 will be the first month when Jordan's total savings exceeds $150.
The fifth month will be April. Jordan's total savings will be enough in April.
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The attached shows a spreadsheet that computes Jordan's amount of savings each month, and his running total. Once the formulas are written, they can be copied down as far as required to see where the total savings is enough.
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Answer:
A. 0.2222
B. Repeat indefinitely
Step-by-step explanation:
A. We have that Scott has 9 pieces in total and he eats 2 of them. That means he eats 2 <em>out of </em>the 9, so we have 2 ÷ 9. (see attachment)
The decimal form is: 0.2222.
B. Clearly, we can see that throughout the long division, we keep getting 20 - 18 = 2, which makes another 20 and so on. So, this will repeat indefinitely.
