There 2 ways to solve this
1- Directly :
80% of water in the fresh berries è 20% of water in the dried berries
36 Ibs of the fresh berries è X Ibs of the dried berries
X = <span> = 9 Ibs</span>
<span>2- </span>If you do not understand the first method, the second one is more explicit:
First, we gonna calculate the weight of the berries without water (dehydrated):
<span>36 * 80% = 28.8 Ibs (of water in the berries)</span>
Then:
<span>36 – 28.8 = 7.2 Ibs (of completely dehydrated berries)</span>
Next, we gonna add 20% of water in the dehydrated berries:
X (total weight of dried berries) è 100%
7.2 Ibs of dehydrated berries è 80%
X = <span> </span> = 9 Ibs