Question 677232
IN FUTURE PUT QUESTIONS SEPARATELY
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A1. Let x lb of $5 coffee is used.
Cost of 70 lb of $11 coffee = $70 * 11 = $770
Cost of x lb of $5 coffee = $5x
Total cost = 770 + 5x
Total weight = (x+70) lb
Cost of (x+70) lb of $7 coffee = (x+70)*7 = 7x + 490
By condition, 7x + 490 = 770 + 5x
7x - 5x = 770 - 490
2x = 280
x = 280 / 2 = 140 lb
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A2. Let x ml of 35% solution has been mixed with y ml of 65% solution to get (x+y) ml of 45% solution
Therefore, x*35/100 + y*65/100 = (x+y)*45/100
or, (35x + 65y)/100 = (45x+45y)/100
or, 35x + 65y = 45x + 45y
or, 35x - 45x = 45y - 65y
or, -10x = -20y
or, x/y = (-20)/(-10)
or, x/y = 2/1
Therefore the ration between 35% solution and 65% solution should be 2:1.