8. Mark can clean his father's office in 30 minutes. His younger sister Lynn can clean the office in 40 minutes. How long will it take the two of them together to clean the office?

3. What is the x-coordinate of the vertex of y = 2 (x + 8) (x - 10) ?

What is the range of the following set? 48, 47, 54, 55, 52, 48, 46, 53, 45

The scores of 12th-grade students on the national assessment of educational progress year 2000 mathematics test have a distribution that is approximately normal with mean of 300 and standard deviation of 35. a. choose one 12th-grader at random.

What is this equation 390*0.1?

Estimate the quotient 4 : 1,165

A triangle has sides of lengths 48 mm, 55 mm, and 73 mm. Is it a right triangle?

Divide 3765 by 8 and write the remainder as a fraction

Is-5/6 closer to - 1 or - 1/2

Ralph sold brownies for $0.12 a piece in order to earn money to buy baseball cards. If the cards cost $0.36 per pack, and if Ralph had no money left over after buying them, what is the least number of brownies he must have sold

Kathleen makes 144 cupcakes each week. Of these she sales 25 each week and gives away the rest. Write a linear function that represents the number of cupcakes Kathleen has given away over time.