Asupermarket sells 4 apples for $3 and 3 oranges for $4 . if lyndsey buys 12 apples and 12 oranges , how much money will she spend on fruit?

Use equivalent fractions. 4/3 needs to be 12/? you dont know how much twelve apples cost so divide 12 by 4 and get 3 and multiply that by 3 and get $9 for 12 apples. for oranges the fraction would be 3/4 needs to be 12/? and divide 12 by 3 and get 4 and multiply 4 by 4 and get 16. 

So your final answer answers are $9 for apples and $16 for oranges.