Step 1: Understanding the Binomial Coefficient The binomial coefficient \( C_n^r \) is defined as: \[ C_n^r = \frac{n!}{r!(n-r)!}, \] and it is defined when \( r \leq n \). In this case, the binomial coefficient is \( C_{17-x}^{3x+15} \), and we want to find for which values of \( x \) this coefficient is defined as an integer.
Step 2: Analyzing the Inequality For the binomial coefficient \( C_{17-x}^{3x+15} \) to be valid, we need to ensure that the lower index \( 3x + 15 \) is less than or equal to the upper index \( 17 - x \). This gives us the inequality: \[ 3x + 15 \leq 17 - x. \]
Step 3: Solving the Inequality Now, we will solve the inequality: \[ 3x + 15 \leq 17 - x. \] First, add \( x \) to both sides: \[ 3x + x + 15 \leq 17 \quad \Rightarrow \quad 4x + 15 \leq 17. \] Next, subtract 15 from both sides: \[ 4x \leq 2. \] Now, divide both sides by 4: \[ x \leq \frac{2}{4} = \frac{1}{2}. \] Thus, \( x \leq \frac{1}{2} \).
Step 4: Finding the Values of \( x \) Since \( x \) must be an integer, the possible values for \( x \) are \( x = 0, 1 \). These are the only values that satisfy the condition. Thus, the number of values of \( x \) for which \( C_{17-x}^{3x+15} \) is defined is 5. Thus, the correct answer is (A).
The number of factors of 1800 that are multiple of 6 is …………. .
The number of real solutions of the equation \((x^2 - 15x + 55)^{x^2 - 5x + 6} = 1\) is __________.
Let \( ABC \) be a triangle right-angled at \( B \) with \( AB = BC = 18 \). The area of the largest rectangle that can be inscribed in this triangle and has \( B \) as one of the vertices is _____________.
A fruit seller has oranges, apples, and bananas in the ratio 3:6:7. If the number of oranges is a multiple of both 5 and 6, then the minimum number of fruits the seller has is ______________.
The number of integer solutions of the equation $x_1 + x_2 + x_3 + x_4 = 50$, where $x_1 \ge 1$, $x_2 \ge 2$, $x_3 \ge 0$, and $x_4 \ge 0$, is:
The number of factors of 1800 that are multiple of 6 is …………. .
The number of real solutions of the equation \((x^2 - 15x + 55)^{x^2 - 5x + 6} = 1\) is __________.
In a group of 150 students, 52 like tea, 48 like juice, and 62 like coffee. If each student in the group likes at least one among tea, juice, and coffee, then the maximum number of students that like more than one drink is _______________.
Let \( ABC \) be a triangle right-angled at \( B \) with \( AB = BC = 18 \). The area of the largest rectangle that can be inscribed in this triangle and has \( B \) as one of the vertices is _____________.