First, let's find out how many words Grace and Jenny can type in a given time.
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Grace's typing speed:
- Grace types 100 words in 2 minutes.
- This means her typing speed is: \[ \frac{100 \text{ words}}{2 \text{ minutes}} = 50 \text{ words per minute} \]
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Jenny's typing speed:
- Jenny takes 40 seconds longer than Grace to type 100 words.
- Grace takes 2 minutes (which is 120 seconds) to type 100 words. Therefore, Jenny takes: \[ 120 \text{ seconds} + 40 \text{ seconds} = 160 \text{ seconds} \]
- Her typing speed is: \[ \frac{100 \text{ words}}{160 \text{ seconds}} = \frac{100 \text{ words}}{2.67 \text{ minutes}} \approx 37.5 \text{ words per minute} \]
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Words typed by Grace in 30 minutes: \[ \text{Words by Grace} = 50 \text{ words/minute} \times 30 \text{ minutes} = 1500 \text{ words} \]
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Words typed by Jenny in 30 minutes: \[ \text{Words by Jenny} = 37.5 \text{ words/minute} \times 30 \text{ minutes} = 1125 \text{ words} \]
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Difference in words typed: \[ \text{Difference} = \text{Words by Grace} - \text{Words by Jenny} = 1500 - 1125 = 375 \text{ words} \]
Thus, after 30 minutes, Grace will have typed 375 more words than Jenny.