An instrument store gives a 10% discount to all students off the original price of an instrument. During a back to school sale an additional 15% is taken off the discounted price. A student purchases a flute for $306. How much did it originally cost?
Write out an equation with the percentages as decimals being subtracted and the term "x" as the unknown original price. x -0.10x -0.15(x -0.10x) = 306 distribute -0.15 to the parenthesis x -0.10x -0.15x +0.015x = 306 Add all x terms together (x is equal to 1.0x) 0.765x = 306 Divide 306 by 0.765 to solve for x x = $400 which was the original price
How many kilograms are in 6 moles of Carbon?
Obtain the molecular weight of Carbon from the periodic table. (the number above the element) Carbon: 12 g/mol Since moles are in the denominator of the unit, multiply 12 g/mol by 6 moles to cancel out the moles (12 g/mol) x (6 mol) = 72 g Convert grams to kilograms 1 kg = 1000 g Multiply 72 g by 1kg/1000g to cancel out grams (72 g) x (1 kg/ 1000 g) = 0.072 kg
Solve the following equation 4(-3x -2) - (x -6) = -4(5x + 8) + 12
First distribute the terms to the parenthesis -12x -8 -x +6 = -20x -32 +12 Combine like terms on both sides of the equation -13x -2 = -20x -20 Put all "x" terms on one side of the equation. Add 20x to -13x and add 2 to -20 to get all like terms on the same side 7x = -18 divide -18 by 7 to solve for the term x x= -18/7