Answer: Third option.
Please, see the detailed solution in the attache file.
Thanks
Answer:
10 calories were burned for each minute of jogging and 10 calories were burned for each minute of cycling.
Step-by-step explanation:
Let be "j" the amount of calories Shelly burned for each minute of jogging and "c" the amount of calories Shelly burned for each minute of cycling.
Set up a system of equations:

You can apply the Elimination method: multiply the first equation by -2, then add the equations and solve for "c":

Now, substitute the value of "c" into any original equation and solve for "j":

Speed = distance / time
30 = d / 2.5
30 * 2.5 = d
75 = d
40 = d / 1.875
40 * 1.875 = d
75 = d
50 = d / 1.5
50 * 1.5 = d
75 = d
60 = d / 1.25
60 * 1.25 = d
75 = d
24 = 75 / time
time = 75/24
time = 3.125 hours