How much water should be added to 18ml of 10% alcohol solution to reduce to reduce the concentration to 9%

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Acentral angle measuring 160 degrees intercepts an arc in a circle whose radius is 4. what is the length of the arc the circle formed by this central angle? round the length of the arc to the nearest hundredth of a unit. a) 4.19 units b) 6.28 units c) 12.57 units d) 12.57 square units

Write as a product of two polynomials. 2(3–b)+5(b–3)^2