Robyn and Shruti both run on the cross country team. Robyn runs 2 miles every day. Shruti starts her week with a 3-mile run and runs 1 mile every day, even on the day she runs the 3 miles. If M is the number of miles run during the week, and d id the number of days the girl has run this week, for which girl is the relationship between M and d multiplicative?
A. Shruti, because M = d +3
B. Shruti, because M = 3d
C. Robyn, because M = 2d
D. Robyn, because M = d + 2
Can someone show me how to solve?
its trash
trash math
To determine which girl has a multiplicative relationship between M (number of miles run during the week) and d (number of days the girl has run this week), we can look at the given information.
We know that Robyn runs 2 miles every day, so the relationship between M and d for Robyn would be M = 2d.
On the other hand, Shruti starts her week with a 3-mile run and runs 1 mile every day, including the day she runs the 3 miles. So on that day, she runs a total of 3 + 1 = 4 miles. For the other days, she runs only 1 mile a day. Therefore, the relationship between M and d for Shruti would be M = 4 + 1 * (d - 1) = 4 + (d - 1) = 3 + d.
Comparing these two relationships, we can see that the relationship between M and d for Shruti (M = 3 + d) is multiplicative, while the relationship for Robyn (M = 2d) is not multiplicative.
Therefore, the answer is B. Shruti, because M = 3 + d.
Robyn: M=2d
Shruti: M=3+d
Since Shruti adds a constant 3 miles to her multiple of d, her relationship is not strictly multiplicative.