We can write out a formula in order to solve this. Since sum represents addition, if x represents the unknown number, we can write the formula: x+51=-21. Then, to solve for x, you would subtract 51 from both sides to get x=-72 which is the final answer.
Answer
Sal spent 43 minutes jogging per day last week.
Elena spent 45 minutes jogging per day last week.
Step-by-step
Part 1: Find the number of minutes Sal jogged.
1. Find the number of minutes out of the week that were spent jogging.
240 - 25 = 215
Sal spent 215 minutes jogging.
2. Find the number of minutes per day he spent jogging.
215 / 5 = 43
Sal spent 43 minutes jogging per day last week.
Part 2: Find the number of minutes Elena jogged.
1. Find the number of minutes out of the week that were spent jogging.
300 - 15(5) = 300 - 75 = 225
Elena spent 225 minutes jogging.
2. Find the number of minutes per day she spent jogging.
225 / 5 = 45
Elena spent 45 minutes jogging per day last week.
Answer:

Step-by-step explanation:
Area = pi*r^2
Area = pi*9^2
Area = 
Answer:
0.012t + 28 = 30
Step-by-step explanation:
The depth starts at 28 meters. The amount of increase in t minutes will be 0.012t, so the total depth after t minutes is ...
0.012t +28
We want to find when that is equal to 30, so the appropriate equation is ...
0.012t +28 = 30