Chapter 12.2, Problem 13R

To determine

The percentage of the total number of rods that are triggered.

Answer to Problem 13R

  $75\%$

Explanation of Solution

Given info:

Total number of rod cells is $120,000,000=1.2\times {10}^{8}cells$ .

Number of rod cells triggered is $90,000,000=9.0\times {10}^{7}cells$ .

Formula used:

Formula to calculate percentage is

  $\frac{Part}{Whole}\times 100=\%$

Calculation:

By using the formula of percentage, percentage of rod cells triggered is

  $=\frac{9.0\times {10}^7}{1.2\times {10}^8}\times 100=75\%$

Conclusion: The percentage of the total number of rods that are triggeredis $75\%$ .