They ran different shapes and materials through a wind tunnel to see which shape and material would decrease energy output so that it takes in equal COthan it puts out.
Answer:
Estimated number of indigenous faults remaining undetected is 6
Explanation:
The maximum likelihood estimate of indigenous faults is given by,
here,
= the number of unseeded faults = 6
= number of seeded faults = 30
= number of seeded faults found = 15
So NF will be calculated as,

And the estimate of faults remaining is
= 12 - 6 = 6
Answer:
I'm pretty sure it's letter d