She has 4 groups all together. 3 groups with ten rocks each and 1 group with 8 rocks(8/10).
1. We assume, that the number 128 is 100% - because it's the output value of the task.
<span>2. We assume, that x is the value we are looking for. </span>
<span>3. If 128 is 100%, so we can write it down as 128=100%. </span>
<span>4. We know, that x is 51% of the output value, so we can write it down as x=51%. </span>
5. Now we have two simple equations:
1) 128=100%
2) x=51%
where left sides of both of them have the same units, and both right sides have the same units, so we can do something like that:
128/x=100%/51%
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.
7. Solution for what is 51% of 128
128/x=100/51
<span>(128/x)*x=(100/51)*x - </span>we multiply both sides of the equation by x
<span>128=1.96078431373*x - </span>we divide both sides of the equation by (1.96078431373) to get x
<span>128/1.96078431373=x </span>
<span>65.28=x </span>
x=65.28
<span>now we have: </span>
<span>51% of 128=65.28</span>
Answer:
Negative infinity to infinity, 3 to infinity.
