Answer:
2 pounds of coffee costing $4 should be mixed with 3 pounds of coffee costing 4.50 a pound to obtain a mixture costing $4.30 a pound.
Step-by-step explanation:
Given that coffee costing $4 a pound mixed with 3 pounds of coffee costing $4.50 a pound . we have to find the number of pounds of coffee mixed with 3 pounds of coffee costing $4.50 a pound to obtain a mixture costing $4.30 a pound.
Let x be the pounds of coffee mixed.
Cost of coffee of 3 pounds costing $4.50 a pound is 3(4.50)=$13.5
Total weight of mixture=x+3
The cost per pound of the mixture will be the total value of the coffee in the mixture divided by the total weight of the mixture which is 4x+13.5 divided by total weight 3 + x.
∴ A/Q the equation becomes

⇒ 4x+13.5=4.30(3)+4.3x
⇒ 0.6=0.3x
⇒ x=2
Hence, 2 pounds of coffee costing $4 should be mixed with 3 pounds of coffee costing 4.50 a pound to obtain a mixture costing $4.30 a pound.
It’s between two and three which might turn out to be a decimal
-5n-8(1+7n)=8
Let's simplify everything.
-5n-8-56n=8
Put the variables on one side and the numbers on the other.
-5n-56n=8+8
Combine like terms.
-61n=16
n=-16/61
Hope I helped! :)
Lets look at the number. 76.78. In each of the different place holders the number is higher than 5. Lets do some examples. 74 rounded to the nearest whole number is going to be 70. 76 rounded to the whole number will be 80. The .78 in your question also contributes.
Answer: 80