Answer:
thats a easy question
Step-by-step explanation:
Answer: 65 grams
Step-by-step explanation:
If 130 grams of a gold alloy (a mixture of gold and one or more other metals) containing 85% pure gold, that means the percentage of other metals will be;
100 - 85 = 15 %
You should first calculate the amount of gold that makes up this percentage.
That is, 85% of 130 grams.
85/100 × 130 = 110.5
Then, let X be what will be added to the above value to make 90%. So,
(110.5 + X) / ( 130 + X ) × 100 = 90
Divide both sides by 100
(110.5 + X) / ( 130 + X ) = 90/100
(110.5 + X) / ( 130 + X ) = 0.9
Cross multiply and open the bracket
110.5 + X = 117 + 0.9X
Collect the like terms
X - 0.9X = 117 - 110.5
0.1X = 6.5
Divide both sides by 0.1
X = 6.5/0.1
X = 65 grams
Therefore, the amount of pure gold that should be added is 65 grams
Answer:
6 gallons
Step-by-step explanation:
1) $30/10 gallons= $3 per gallon
So...
2) $18/3=<u>6 gallons</u>
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Answer:
2nd choice 
is correct.
Step-by-step explanation:
We need to find about which polynomial is represented by the algebra tiles.
so we just need to collect all terms written on tiles then combine them.
Notice that - means -1 and + means +1
Row wise terms are:
Now combine like terms:
Hence 2nd choice is correct.
Answer:
D.) $115
Step-by-step explanation:
9.95 x 4 = 39.8
12.95 x 2 = 25.9
15.95 x 2 = 31.9
39.8 + 25.9 + 31.9 = 97.6
97.6 x 0.18 = 17.568
97.6 + 17.568 = 115.168
115.168 ≈ 115
