If \frac{2a}{3}=\frac{4b}{5}=\frac{3c}{4} then what is the value of \frac{18}{a}\sqrt{a^{2}+c^{2}-b^{2}}?
- A. 3\sqrt{5}
- B. \sqrt{355} ✓
- C. \sqrt{375}
- D. 3\sqrt{15}
Correct Answer: B. \sqrt{355}
Explanation
Let \frac{2a}{3}=\frac{4b}{5}=\frac{3c}{4} = k. Then a = \frac{3k}{2}, b = \frac{5k}{4}, c = \frac{4k}{3}. Substituting into the expression: \frac{18}{3k/2} \sqrt{\frac{9k^2}{4} + \frac{16k^2}{9} - \frac{25k^2}{16}} = \frac{12}{k} \cdot k \sqrt{\frac{1296 + 1024 - 900}{576}} = 12 \sqrt{\frac{1420}{576}} = \frac{12}{24} \sqrt{1420} = \frac{1}{2} \sqrt{355 \times 4} = \sqrt{355}.
Related questions on Arithmetic
- What is the remainder when (17^{25} + 19^{25}) is divided by 18?
- A bottle contains spirit and water in the ratio 1:4 and another identical bottle contains spirit and water in the ratio 4:1. In what rat...
- Let P = 5^5 \times 15^{15} \times 25^{25} \times 35^{35} and Q = 10^{10} \times 20^{20} \times 30^{30} \times 40^{40}. What is the numbe...
- Two students X and Y appeared in a test. The score of X is 20 more than that of Y. If the score of X is 75% of the sum of the scores of X an...
- Question: The product of a natural number N and the number M written by the same digits of N in the reverse order is 252. What is the number...