Answer: 
Step-by-step explanation:
The exponential model for growth is given by :-
, where A = initial value , r = growth rate (in decimal), x = time (in years).
Given: A= 15,500 r= 3.75% = 0.0375
The exponential model for the growth of this population will be :

hence, the required model: 
Speed of trucks= x speed of trains =x-30 A loaded
7 multiply by three u get 21 then add it to the number 28 add u get the answer 49
Answer:
Two times the difference of x and seven plus ten
Step-by-step explanation: