Mrs Lim bought a number of plates at an average price of $6. She decided to buy another plate which cost $18. The average price of all the plates then became $8. What was the total number of plates Mrs Lim bought in all?

Tim's phone service charges $23.06 plus an additional $0.22 for each text message sent per month. if tim's phone bill was $28.56, which equation could be used to find how many text messages, x, tim sent last month?

Damon makes 20 cups of lemonade by mixing lemon juice and water. the ratio of lemon juice to water is shown in the tape diagram. lemon juice\text{lemon juice} lemon juice water\text{water} water how much lemon juice did damon use in the lemonade? cups

Which expression is equivalent to 64 - 9x^2?