1. Ms. P can type 600 words in 15 mins. If Mr. D can type twice as fast as P, how many words he can type in 40 minutes? 2. If x + 3/19 = x/5/20, then x = ? 3. 2/5 of A’s salary is... 1. Ms. P can type 600 words in 15 mins. If Mr. D can type twice as fast as P, how many words he can type in 40 minutes? 2. If x + 3/19 = x/5/20, then x = ? 3. 2/5 of A’s salary is equal to B’s salary and 7/9 of B’s salary is equal to C’s salary. If the sum of the salaries of all three is Rs. 77,000, then B's salary is? 4. A sum was put at simple interest at a certain rate of interest for 2 years. Had it been put at 3% higher rate, it would have fetched Rs. 300 more. Find the sum. 5. If (x+1)^2 = 100, then x^2 + 1/x^2 = ? 6. A room is 4 m long and 3 m 50 cm wide. How many square meters of carpet is needed to cover the floor of the room? 7. If the ratio of measures of two acute angles in a right-angled triangle is 3:7, then the smallest angle is? 8. In a jar, if 1/2 of the marbles are red, 1/4 are white and 1/5 are blue, what is the fraction of marbles which are neither red, white, nor blue?
Understand the Problem
The questions are a mix of mathematical problems involving percentages, ratios, interest calculations, and geometry. Each question requires solving for a specific value based on the provided information or formulas.
Answer
Mr. D can type $3200$ words in $40$ minutes.
Answer for screen readers
Mr. D can type 3200 words in 40 minutes.
Steps to Solve
- Calculate Mr. D's Typing Speed
Ms. P can type 600 words in 15 minutes. First, we find her typing speed:
$$ \text{Speed of P} = \frac{600 \text{ words}}{15 \text{ minutes}} = 40 \text{ words per minute} $$
Since Mr. D types twice as fast as Ms. P:
$$ \text{Speed of D} = 2 \times 40 = 80 \text{ words per minute} $$
- Determine the Time for Mr. D
Now, we need to find how many words Mr. D can type in 40 minutes:
$$ \text{Words typed by D} = \text{Speed of D} \times \text{Time} = 80 \text{ words/minute} \times 40 \text{ minutes} $$
- Calculate Words Typed by Mr. D
Now we calculate the total words:
$$ \text{Words typed by D} = 80 \times 40 = 3200 \text{ words} $$
Mr. D can type 3200 words in 40 minutes.
More Information
This problem illustrates how to calculate typing speeds and how they scale with time. It shows the relationship between typing efficiency and productivity over different time intervals.
Tips
- Miscalculating speeds: Ensure to divide the total output by the total time correctly.
- Confusing order of operations: Make sure to follow the order of operations when performing calculations.
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