Jennifer bought a textbook with 2/7 of her money. She then bought a notebook with 3/5 of her remaining money and was left with $12. How much money did she start with.
x=amount of money at first price of a textbook=2/7 x her remaining money after she bought his textbook was: x -2/7 x=5/7 x price of the notebook: (3/5)(5/7 x)=3/7x her remaining money after she bought his notebook was $12
We can suggest this equation: 2/7 x +3/7 x + 12=x
lowest common multiple=7 2x+3x+84=7x 7x-2x-3x=84 2x=84 x=84/2 x=42