Easy 7th grade math

Find the value of x.

Janet is mixing a 15% glucose solution with a 35% glucose solution. this mixture produces 35 liters of a 19% glucose solution. how many liters of the 15% solution is januet using in the mixture? a. 25 liters c. 28 liters b. 7 liters d. 10 liters

Divide. reduce the answer to lowest terms.5 2/3 ÷ 3 1/9

You are at a restaurant and owe $56.20 for your meal. you want to leave an 18% tip. approximately how much is your tip?