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Zorluk: Çok zorRatios, Rates, and Proportions

A renewable energy facility stores electricity in three separate battery modules: Module XX, Module YY, and Module ZZ. The ratio of the initial energy stored in Module XX to Module YY is 2:32 : 3, and the ratio of the initial energy stored in Module YY to Module ZZ is 5:85 : 8. Each module discharges its stored energy at a constant individual rate. Operating alone, Module YY can completely discharge its initial stored energy in 55 hours. Module XX discharges energy at a rate 3313%33\frac{1}{3}\% greater than Module YY, and Module ZZ discharges energy at a rate 25%25\% less than the combined discharge rate of Modules XX and YY. If all three modules begin discharging simultaneously, how many hours will it take to completely discharge the total initial energy stored across all three modules?

  1. A
    3.5 hours
  2. 4 hoursCevap
  3. C
    5.25 hours
  4. D
    6 hours
  5. E
    7.5 hours

Cevap

4 hours
To find the total time required, first unify the two given ratios. Since X:Y=2:3X : Y = 2 : 3 and Y:Z=5:8Y : Z = 5 : 8, express both ratios with a common value for YY (1515). This yields X:Y:Z=10:15:24X : Y : Z = 10 : 15 : 24, so total energy is 10k+15k+24k=49k10k + 15k + 24k = 49k. Next, determine rates in terms of kk: Module YY discharges 15k15k in 55 hours, so its rate is 3k3k units/hr. Module XX discharges at a rate 3313%33\frac{1}{3}\% greater than Module YY, giving 3k×43=4k3k \times \frac{4}{3} = 4k units/hr. The combined rate of XX and YY is 4k+3k=7k4k + 3k = 7k units/hr. Module ZZ discharges at 25%25\% less than this combined rate, giving 7k×0.75=5.25k7k \times 0.75 = 5.25k units/hr. The simultaneous discharge rate of all three modules is 4k+3k+5.25k=12.25k4k + 3k + 5.25k = 12.25k units/hr. Dividing total energy 49k49k by 12.25k12.25k gives exactly 4 hours.

Adım Adım Çözüm

1
Determine the unified initial energy ratio among all three modules.
Energy ratio Module XX : Module YY : Module ZZ = 10:15:2410 : 15 : 24, giving a total initial energy of 49k49k units.
Module X:Y=2:3=10:15X : Y = 2 : 3 = 10 : 15 and Module Y:Z=5:8=15:24Y : Z = 5 : 8 = 15 : 24. Combining these gives X:Y:Z=10:15:24X : Y : Z = 10 : 15 : 24 for a common constant kk.
2
Calculate the individual discharge rate of Module Y.
Discharge rate of Module YY = 3k3k energy units per hour.
Module YY has 15k15k energy units and discharges completely in 55 hours, so RateY=15k5=3k\text{Rate}_Y = \frac{15k}{5} = 3k.
3
Determine the discharge rates of Module X and Module Z.
Discharge rate of Module XX = 4k4k units per hour; discharge rate of Module ZZ = 5.25k5.25k units per hour.
Module XX rate is 3313%33\frac{1}{3}\% greater than Module YY: RateX=3k×(1+13)=4k\text{Rate}_X = 3k \times \left(1 + \frac{1}{3}\right) = 4k. Combined rate of XX and YY is 4k+3k=7k4k + 3k = 7k. Module ZZ rate is 25%25\% less than this combined rate: RateZ=7k×0.75=5.25k\text{Rate}_Z = 7k \times 0.75 = 5.25k.
4
Calculate total combined discharge rate and total time required.
Combined rate = 12.25k12.25k units per hour; Total time = 44 hours.
Total rate =4k+3k+5.25k=12.25k= 4k + 3k + 5.25k = 12.25k units per hour. Total time =Total EnergyTotal Rate=49k12.25k=4= \frac{\text{Total Energy}}{\text{Total Rate}} = \frac{49k}{12.25k} = 4 hours.

Anahtar Kavram

Combining multi-part ratios into a unified scale and calculating combined work rates with percentage adjustments
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