Please help, brainliest will be award to actual answers, try explaining

A.  

Step-by-step explanation:

A positive rate of change is when it goes from one interval to another, and the y-variables are going up, or the change is positive. On this graph, it is when y goes up from one variable to another. For a, it says when x=0 to x=1. You look at the y-variables for that interval, and you see that it is positive because it is going from 50 to 75 and it is going up. F is x=2 to x=3. The y-variables are 40 and 65. This time, it is also going up. These are the only times where the y-variables are going up, or the rate of change is positive.  

marco saved more.   he saved $35 more.

step-by-step explanation:

1+2+3+4+5+6+7+8+9+10 = 55

2*10 = 20

55-20 = 35