supatsarah 3 years ago can anyone help me with a couple question's about rate of change?

1. supatsarah

Cathy lives in a state where speeders are fined \$11 for each mile per hour over the speed limit. Cathy was given a ticket for \$99 for speeding on a road where the speed limit is 65 miles per hour. How fast was Cathy driving? 71 mph 79 mph 74 mph 78 mph

2. zepdrix

Let x be the number of "speeding" miles Cathy is going. 11x <-- this is 11\$ for each "speeding" mile. So if Cathy was given a \$99 ticket, we could write an equation like this: 11x=99 \$11 per mile equals 99 total dollars. Then let's solve for x! Hmm if the speed limit is 65, we our final step will be to add x to 65.

3. supatsarah

@zepdrix what's x

4. supatsarah

74 mph got it.

5. zepdrix

Yay gj \c:/

6. supatsarah

Forrest Lumber purchased a table saw for \$810. After 2 years the saw had a depreciated value of \$630. What is the amount of yearly depreciation? @zepdrix can you help me with this? \$90 \$75 \$180 \$105