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The sum of 5consecutive even numbers is 100. what is the first number in this sequence?

How many liters of peroxide should be added to 12 liters of an 8% peroxide solution so that the resulting solution contains 16% peroxide?   original added new amount of peroxide 0.96 liters x 0.96 + x amount of solution 12 liters x 12 + x 0.18 liter 1.14 liters 1.92 liters 2.10 liters

Is a triangle with sides of length 6ft, 21 ft, 23 ft. a right triangle?