Mr. and Mrs. Miller both get in their cars and begin to drive at the same time. Mr. Miller is 280 mi from their house and drives directly home at a constant rate of 40 mph. Mrs. Miller is at their house and drives away from the house at a constant rate of 30 mph.

Let d represent distance from home, and let t represent time in hours.

Which system models this situation?

A.

d = 280 + 40t
d = 30t

B.

d = 280 − 30t
d = 40t

C.

d = 280 − 40t
d = 30t

D.

d = 280 − 40t
d = 280 + 30t

Question

Mr. and Mrs. Miller both get in their cars and begin to drive at the same time. Mr. Miller is 280 mi from their house and drives directly home at a constant rate of 40 mph. Mrs. Miller is at their house and drives away from the house at a constant rate of 30 mph.

 

Let d represent distance from home, and let t represent time in hours.

 

Which system models this situation?
	
	
 
A.
	

d = 280 + 40t
d = 30t
	
 
B.
	

d = 280 − 30t
d = 40t
	
 
C.
	

d = 280 − 40t
d = 30t
	
 
D.
	

d = 280 − 40t
d = 280 + 30t

anonymous · Answer

C is the choice as Mr. Miller is driving towards home and as time goes on his distance from home comes down.In case of Mrs. Miller as she is driving away , her distance will uniformly increase with time independent of Mr. Miller's distance.