Let Karen works x hours baby sitting
So, she worked (18-x) hours giving music lessons
So,
According to question
5x + 12(18-x)=139
This gives
7*x=77
x=11
So,
<span>Karen worked <em>11 hours baby sitting </em>and (18-11)=7 hours giving music lessons</span>
Treat this like a slope formula. Y2-y1 divided by x2-x1.
Your y2 value is the second population
Y1= value of first population.
X2= second year they give
X1= first year they give.
4700-3650
_________
2014-2012
1050
____
2
525 is the increase a year