Binomial expansion for positive integer n Quiz

1. Evaluate $\binom73$.

• A. $21$
• B. $35$
• C. $42$
• D. $210$

2. Find the coefficient of $x^2$ in $(1+2x)^5$.

• A. $40$
• B. $20$
• C. $80$
• D. $10$

3. What is the coefficient of $x^3$ in $(2-x)^4$?

• A. $8$
• B. $-4$
• C. $-8$
• D. $-32$

4. The first three terms of $(1+ax)^6$ are $1+12x+bx^2$. Find $a$ and $b$.

• A. $a=12$, $b=60$
• B. $a=2$, $b=60$
• C. $a=2$, $b=15$
• D. $a=6$, $b=15$

5. $X\sim B\left(4,\frac12\right)$. What is $P(X=3)$?

• A. $\frac38$
• B. $\frac{1}{16}$
• C. $\frac{3}{16}$
• D. $\frac14$