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# Math word problem help, please!?

Topic: Math word problem help, please!?
June 20, 2019 / By Deena
Question: The Question: A woman deposits \$50,000 in a savings account with 4% continuously compounded interest. How many years must she wait until the balance has doubled? There are many applications of the growth (and decay) formulas. Interest is just one of the applications of exponential functions. I am trying to understand how to evaluate logarithmic expressions and solve logarithmic equations.

Brogan | 8 days ago
A(t) = A(0)•e ͬͭ A(0) = 50,000, r = 0.04, A(t) = 2•50,000 = 100,000 and we want to solve for t. So 100000 = 50000•e^(0.04t) Divide by 50000. 2 = e^(0.04t) Take natural logs of both sides: ln 2 = 0.04t, so t = ln 2/0.04 = 17.33 years approx
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Originally Answered: Math word problem help?
We are given two points (x being price, y being units sold with a maximum of 40). With two points, we can come up with a linear equation: (740, 40) and (779, 37) y = mx + b Slope is change in y over change in x, so: (40 - 37) / (740 - 779) 3 / (-39) -1/13 Now that we know the slope, using one of the points for x and y, we can solve for b: y = mx + b 37 = (-1/13)(779) + b Multiply both sides by 13: 481 = -779 + 13b 1260 = 31b b = 1260 / 13 So your equation is: y = (-1/13)x + 1260/13 That's the answer to part a. Part b asks us to graph it and predict how many units will go at \$792. Putting it into a graph web site, we get: http://www.wolframalpha.com/input/?i=y+%... Looks like it will be about: 36 units Part c asks us to predict units rented if rent is lowered to \$766. Using the same graph, about: 38 units. And you can do the math if you want to make sure.
Originally Answered: Math word problem help?
a) (740,40) and (779, 37) are points given Slope = -3/39 = -1/13 x-40 = (-1/13)(p-740) 13x = 740-p+520 = -p+1260 x(p) = -p/13 + 96.9 b) x(792) = 36 units c) x(766) = 38 units
Originally Answered: Math word problem help?
(a.) x(p) = 40 - (p-740)/13 (b.) x(p) = 40 - (792 - 740)/13 x(p) = 36 units (c.) x(p) = 40 - (766 - 740)/13 x(p) = 40 - 2 = 38 units

Alison
If something is 40% smaller, you only subtract 40%. So 40% of 40 energy is sixteen: you try this via multiplying 40 via 0.4. the respond may be 40 - sixteen = 24 A shorter way might only be to multiply via 40 via 0.6, for the reason that it is a million-0.4.
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