Question

at a circus, 99.99% of knife-throwers knives hit the target. if the knife-thrower throws 20 knives per show and preforms 250 shows per year, how many knives miss the target over 10 years?
0
0.5
1
5

Answer 1

To find out how many knives miss the target over 10 years, we can follow these steps:

1. **Calculate the total number of knives thrown in 10 years**:
The knife-thrower throws 20 knives per show and performs 250 shows each year. Therefore, the total number of knives thrown per year is:
\[
20 \, \text{knives/show} \times 250 \, \text{shows/year} = 5000 \, \text{knives/year}
\]
Over 10 years, the total number of knives thrown is:
\[
5000 \, \text{knives/year} \times 10 \, \text{years} = 50000 \, \text{knives}
\]

2. **Calculate the number of knives that miss the target**:
Given that 99.99% of knives hit the target, the percentage of knives that miss is:
\[
100\% - 99.99\% = 0.01\%
\]
The decimal equivalent of this percentage is:
\[
0.01\% = 0.0001
\]
Therefore, the expected number of knives that miss the target is:
\[
50000 \, \text{knives} \times 0.0001 = 5 \, \text{knives}
\]

So, over 10 years, the estimated number of knives that miss the target is **5**.