This is not a full question. If you were given the amount at the begining of 1970 (we'll call it x) and the amount at the end of 1980 (we'll call it y), we should solve them accordingly:
y-x=? (calling the answer a)
a/y=%(not answer yet, call this b)
b+100=answer
41.666666666666..............
Answer:
answer for number a is 3/2
answer for number b is 6
answer for number c is 8
B (1,0). -2 + 3 = 1. -2 + 2 = 0.
The equasion she would use would be 60,000 = 1000x + 40,000
this would means 1,000 times a number plus the 40,000 shes already getting equals 60,000