Question 28
Kelvin the frog jumps along the number line starting at $0$. Every time he jumps, he jumps either one unit left or one unit right. For example, one sequence of jumps might be $0 \rightarrow -1 \rightarrow 0 \rightarrow 1 \rightarrow 2 \rightarrow 3 \rightarrow 2$.
How many ways are there for Kelvin to make exactly $10$ jumps and land on a prime number? (The prime numbers are the sequence $2, 3, 5, 7, \ldots$ Negative numbers are not considered prime.)
How many ways are there for Kelvin to make exactly $10$ jumps and land on a prime number? (The prime numbers are the sequence $2, 3, 5, 7, \ldots$ Negative numbers are not considered prime.)