Answer:
Martha exercises 310 minutes more than Greg in a 31-day month!
Explanation:
30x
40x
Where x equals the number of days.
Let's plug it in:
30(31) = 930
40(31) = 1240
Let's subtract:
1240 - 930 = 310
MEANING Marta exercises 310 minutes more than Greg in a 31-day month!