Since Sylvanite only contains 28% gold by mass, then to obtain 81.0 grams of gold, x amounts of sylvanite must be mined. To determine x, we divide 81 grams by 28%. This equation is shown below:
0.28X = 81
X = 81/0.28
X = 289.29 grams
Therefore, 289.29 grams of sylvanite must be dug up to obtain 81 grams of gold.
        
             
        
        
        
I = PRT.....rearrange.....P = I / RT
P = 51 / (0.0425* 2).....I used 2 because 24 months = 2 yrs
P = 51 / 0.085
P = 600 <===
        
             
        
        
        
Answer:
setup below, you'll have to do the final calculation 
Step-by-step explanation:
first perform the operation in parenthesis 
2+39= 41
 then do the multiplication 3 x 41
in general do calculations in this order
1. Parenthesis 
2. Multiplication 
3. Division 
4. Addition 
5. Subtraction 
working from left to right
 
        
             
        
        
        
Volume of cylinders = pi x r^2 x height  Simplifying the ratio: 1.6/3 = 16 / 30 (multiply and divide by 10 to remove the decimal)  Volume Ratio = 512:27