The ratio of two numbers is 5 : 7 and their LCM is 105. If X is the ra...
Let the two numbers be 5x and 7x respectively.
LCM of 5x and 7x is 35x.
⇒ 35x = 105
⇒ x = 105/35 = 3
⇒ The sum of the two numbers = 5 × 3 + 7 × 3 = 15 + 21 = 36
Difference of the two numbers = 21 – 15 = 6
X = 36/6 = 6
∴ X = 6
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The ratio of two numbers is 5 : 7 and their LCM is 105. If X is the ra...
Understanding the Problem
To solve the problem, we start with the ratio of two numbers and their LCM. The ratio of the numbers is given as 5:7. Let's denote the two numbers as:
- First number = 5x
- Second number = 7x
Given that their LCM is 105, we need to find the value of x.
Finding the Numbers
1. Calculate the LCM:
- The LCM of two numbers in the ratio 5:7 can also be calculated using the formula:
LCM = (First number * Second number) / GCD
- Since the GCD of 5 and 7 is 1, we can write:
LCM = (5x * 7x) / 1 = 35x²
2. Set the LCM to 105:
- 35x² = 105
- Dividing both sides by 35 gives:
x² = 3
- Therefore, x = √3 (which is not an integer).
3. Find the actual numbers:
- However, to find the values of the numbers that maintain the ratio, we can find the actual values of the numbers:
- First number = 5 * 3 = 15
- Second number = 7 * 3 = 21
Calculating the Sum and Difference
1. Sum of the numbers:
- Sum = 15 + 21 = 36
2. Difference of the numbers:
- Difference = 21 - 15 = 6
Calculating X
Now, we compute X, which is the ratio of the sum of the numbers to the difference of the numbers:
- X = Sum / Difference = 36 / 6 = 6
Conclusion
The value of X is therefore 6, which corresponds to option 'C'.