How many pounds of brazilian coffee costing $ 6 per pound must be mixed with 27 lbs of columbian coffee costing $ 4 per pound to produce a mixture costing $ 4.5 per pound.

11 2/3 pounds.

Step-by-step explanation:

Let x pounds be the amount in pounds of Brazilian coffee.

x + 27  is the amount of coffee in lbs after the mixing.

So ,working in  values of dollars, we have:

6x + 4*27 = 4.5(x + 27)

6x + 104 = 4.5x + 121.5

1.5x = 121.5 - 104 = 17.5

x = 17.5/1.5 = 11 2/3 pounds answer

x= 149. 24+7=31. 180-31=149

your welcome

54 km / hours

step-by-step explanation:

we need to convert seconds to hours

60 seconds = 1 minutes

60 minutes = 1hour

15 m         60 second   60 minutes

  * *         = 54000 meters/ hour

second     1 minute             1 hour

now we need to convert meters to km

1000 m = 1 km

54000 m       1 km

*   = 54 km / hours

hour               1000m