It means that 15 times another number equals to your equation.
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A : 1/6 is the answer hope it helps
Answer:
452.39 sq.unit is the area of that circle.
Let x be the number of mm of pure alcohol to be added:
I will add the mm to express the volume in mm
100mm.(19%) + (100%).x mL = (100 mL+x mL).(40%).
Now right again without the %
100.(0.19) + x.(1) = (100+x).(0.4)
19 + x = = 40 + 04x
x - 0.4x = 40 - 19
0.6 x = 21
x = 21/0.6 and x = 35 mL. This te quantity of pure alcohol should to be added to get a solution at 40%.
