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.
Answer:
negative
Step-by-step explanation:
rules:
+ + = +
- - = +
+ - = -
- + = - ----> (-468,256)(183,758)
2ways you can solve that is by multiplying 9 by 1 then by 5 or 9by 5 then by 1
Let's look at work rates per minute.
Together they can paint the wall in x minutes.
Working together, in 1 minute, they do 1/x of the job.
The student who paints the wall in 16 minutes does 1/16 of the job in 1 minute.
The student who paints the wall in 24 minutes does 1/24 of the job in 1 minute.
Together, they do 1/16 + 1/24 of the job in 1 minute, but from above, we see that together, they do 1/x of the job in 1 minute, so 1/16 + 1/24 must equal 1/x. That gives us our equation.
1/16 + 1/24 = 1/x
1/16 * 3/3 + 1/24 * 2/2 = 1/x
3/48 + 2/48 = 1/x
5/48 = 1/x
x = 48/5 = 9.6
Answer: It takes them 9.6 minutes, or about 10 minutes to do the job together.
