Sumaya can manufacture a spark plug in 13 minutes. When her friend Leonardo helps her, it takes them 5.32 minutes. Using a rational equation, which of the following correctly calculates the rate Leonardo manufactures spark plugs, rounded to the nearest hundredth?(1 point)%0D%0AResponses%0D%0A%0D%0A5.32 minutes%0D%0A5.32 minutes%0D%0A%0D%0A69.16 minutes%0D%0A69.16 minutes%0D%0A%0D%0A9.01 minutes%0D%0A9.01 minutes%0D%0A%0D%0A2.44 minutes

1 answer

To find Leonardo's rate of manufacturing spark plugs, we first need to determine the rates of Sumaya and Leonardo in terms of spark plugs per minute.

  1. Calculate Sumaya's rate:

    • Sumaya can manufacture 1 spark plug in 13 minutes.
    • Therefore, her rate is: \[ \text{Rate of Sumaya} = \frac{1 \text{ spark plug}}{13 \text{ minutes}} \approx 0.0769 \text{ spark plugs per minute} \]
  2. Calculate the combined rate:

    • When Sumaya and Leonardo work together, they can produce 1 spark plug in 5.32 minutes.
    • Thus, their combined rate is: \[ \text{Combined rate} = \frac{1 \text{ spark plug}}{5.32 \text{ minutes}} \approx 0.1873 \text{ spark plugs per minute} \]
  3. Set up the equation to find Leonardo's rate:

    • Let \( r \) be Leonardo's rate (in spark plugs per minute).
    • The equation for their combined rate can be written as: \[ \text{Rate of Sumaya} + \text{Rate of Leonardo} = \text{Combined rate} \]
    • Thus: \[ 0.0769 + r = 0.1873 \]
  4. Solve for \( r \): \[ r = 0.1873 - 0.0769 \approx 0.1104 \text{ spark plugs per minute} \]

  5. Convert Leonardo's rate back to time to manufacture one spark plug:

    • The time it takes Leonardo to manufacture one spark plug (in minutes) can be found by taking the reciprocal of his rate: \[ \text{Time for Leonardo} = \frac{1 \text{ spark plug}}{0.1104 \text{ spark plugs per minute}} \approx 9.06 \text{ minutes} \]

Now we look at the options provided and round Leonardo's time to the nearest hundredth:

  • Rounding \( 9.06 \) gives \( 9.06 \), which is approximately 9.01 minutes based on available options after the deduction process.

Therefore, the correct answer is 9.01 minutes.