X - Columbian coffee ( in pounds),
y - Brazilian coffee ( in pounds );
x + y = 100
8.85 x + 3.85 y = 6.55 ( x + y )
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x = 100 - y
8.85 ( 100 - y ) + 3.85 y = 6.55 * 100
855 - 8.55 y + 3.85 y = 655
- 5 y = - 230
y = ( - 230 ) : ( - 5 )
y = 46
x = 100 - 46
x = 54
Answer: 54 pounds of Columbian coffee and 46 pounds of Brazilian coffee should be used.
1% of 120 is 1.2, so 7 *1.2 = 8.4
Also you could set up the proportion 7/100 = x/120 and solve for x.
Answer:
About 9 kilometers
Step-by-step explanation:
15x.6= 9
Answer:
40 hours
Step-by-step explanation:
Lets take "x" as the # of hours it takes the lava to reach the sea
since there is a lava flow of 0.5 kilos per hour
we will multiply "x" with 0.5
0.5x
now the tube system is 20 kilometers long
this means that at a rate of 0.5 kilos per hour the lava will reach the sea once it is 20 kilometers deep
so
0.5x=20
divide "0.5" by both sides to eliminate the coefficient

x=40
it will take 40 hours for the lava to reach the sea
Hope this helps!