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Nachelle just started a running plan where she runs 8 miles the first week and then increases the number of miles she runs by 
5% each week. If she keeps up this plan for 18 weeks, how many total miles would Nachelle have run, to the nearest whole number?
Answer:

Nachelle just started a running plan where she runs 88 miles the first week and then increases the number of miles she runs by 5% 5 \% each week. If she keeps up this plan for 1818 weeks, how many total miles would Nachelle have run, to the nearest whole number?\newlineAnswer:

Full solution

Q. Nachelle just started a running plan where she runs 88 miles the first week and then increases the number of miles she runs by 5% 5 \% each week. If she keeps up this plan for 1818 weeks, how many total miles would Nachelle have run, to the nearest whole number?\newlineAnswer:
  1. Identify: Identify the initial amount of miles and the rate of increase.\newlineNachelle starts with 88 miles and increases her running distance by 5%5\% each week.\newlineInitial miles (a)=8(a) = 8\newlineRate of increase (r)=5%(r) = 5\% or 0.050.05
  2. Determine formula: Determine the formula for the total distance run after nn weeks.\newlineThe total distance run is the sum of a geometric series where each term is 5%5\% greater than the previous term.\newlineThe formula for the sum of the first nn terms of a geometric series is Sn=a(1rn)(1r)S_n = \frac{a(1 - r^n)}{(1 - r)}, where rr is not equal to 11.\newlineIn this case, r=1.05r = 1.05 (since it's a 5%5\% increase, or 1+0.051 + 0.05).
  3. Calculate total distance: Calculate the total distance run after 1818 weeks.\newlineSubstitute the values into the formula:\newlineS18=8(11.0518)/(11.05)S_{18} = 8(1 - 1.05^{18}) / (1 - 1.05)
  4. Evaluate formula: Evaluate the formula.\newlineFirst, calculate 1.05181.05^{18}:\newline1.05182.396561.05^{18} \approx 2.39656
  5. Continue evaluating: Continue evaluating the formula.\newlineNow, substitute 2.396562.39656 into the formula:\newlineS18=8(12.39656)/(11.05)S_{18} = 8(1 - 2.39656) / (1 - 1.05)
  6. Simplify expression: Simplify the expression.\newlineCalculate the numerator:\newline8(12.39656)=8(1.39656)11.172488(1 - 2.39656) = 8(-1.39656) \approx -11.17248
  7. Calculate denominator: Calculate the denominator: 11.05=0.051 - 1.05 = -0.05
  8. Divide to find S18S_{18}: Divide the numerator by the denominator to find S18S_{18}. \newlineS18=11.17248/0.05223.4496S_{18} = -11.17248 / -0.05 \approx 223.4496
  9. Round total distance: Round the total distance to the nearest whole number. S18223S_{18} \approx 223 miles

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