a = amount invested at 5%
b = amount invested at 2%
now, we know the total invested by Mr Wilson was 20000, so whatever "a" and "b" might be, we know that a + b = 20000.
![a + b = 20000\implies b = 20000-a \\\\[-0.35em] ~\dotfill\\\\ \stackrel{\textit{5\% of a}}{\left( \cfrac{5}{100} \right)a}\implies 0.05a~\hfill \stackrel{\textit{2\% of b}}{\left( \cfrac{2}{100} \right)a}\implies \begin{array}{llll} 0.02b\\\\ \stackrel{substituting}{0.02(20000-a)} \end{array}](https://tex.z-dn.net/?f=a%20%2B%20b%20%3D%2020000%5Cimplies%20b%20%3D%2020000-a%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill%5C%5C%5C%5C%20%5Cstackrel%7B%5Ctextit%7B5%5C%25%20of%20a%7D%7D%7B%5Cleft%28%20%5Ccfrac%7B5%7D%7B100%7D%20%5Cright%29a%7D%5Cimplies%200.05a~%5Chfill%20%5Cstackrel%7B%5Ctextit%7B2%5C%25%20of%20b%7D%7D%7B%5Cleft%28%20%5Ccfrac%7B2%7D%7B100%7D%20%5Cright%29a%7D%5Cimplies%20%5Cbegin%7Barray%7D%7Bllll%7D%200.02b%5C%5C%5C%5C%20%5Cstackrel%7Bsubstituting%7D%7B0.02%2820000-a%29%7D%20%5Cend%7Barray%7D)
now, we know the total of earned interest is 550 bucks, so then
Answer:
7 = 49 ÷ r
Step-by-step explanation:
To find the equation that is true when r = 7, we need to find a number after the equals sign that is a multiple of 7.
Multiples of 7:
7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77...
Therefore, the only answer option in which the number after the equals sign is a multiple of 7 is:
7 = 49 ÷ r
To prove this, input r = 7 into each of the equations:
6 = 30 ÷ r
⇒ 6 = 30 ÷ 7
⇒ 6 ≠ 4.285... ← incorrect!
7 = 54 ÷ r
⇒ 7 = 54 ÷ 7
⇒ 7 ≠ 7.714... ← incorrect!
7 = 49 ÷ r
⇒ 7 = 49 ÷ 7
⇒ 7 = 7 ← correct!
9 = 72 ÷ r
⇒ 9 = 72 ÷ 7
⇒ 9 ≠ 10.285... ← incorrect!
Answer: f(x) = -ln(x + 1) + 3
Step-by-step explanation:
We want it to be decreasing, then we can write it, for a start, as:
f(x) = -ln(x)
Ok, now we want it to have a positive y intercept, then we can add a real number inside the logarithm, and other outside: such that f(0) = positive number.
f(x) = -ln(x + 1) + 3
Now, when x = 0 we have:
f(0) = -ln(1) + 3 = 0 + 3 = 3
Then we have a decreasing logarithmic function, with an y-intercept larger than zero.
BCGF is a quadrilateral, angles sum to 360 degrees.
B+C+G+F=360
B and G are right angles, formed by a radius and a tangent.
90+C+90+F=360
C+F=180
C and F are supplementary.
2x + 146 + 4x + 238 = 180
6x + 384 = 180
6x = -204
x = -34
Answer: -34, second choice
