Adding negative numbers

There is a bag with only red marbles and blue marbles. The probability of randomly choosing a red marble is 7 8. There are 72 marbles in total in the bag and each is equally likely to be chosen. Work out how many red marbles there must be.

Devon purchased tickets to an air show for 9 adults and 2 children. the total cost was $206. the cost of a childs ticket was $7 less than the cost of an adults ticket. find the price of an adults ticket and a childs ticket.

Of the 90 students who sat for a test, 24 students passed. Find the ratio of the number of students who passed the test to the number of students who did not. Give your answer in simplest form.

Polynomial difference (ab+4a-6) - (ab-6)

There is same number of pennies, nickels, and dimes in a wallet. Together they make $1.28. How many coins are there in the wallet?

Zina spends 1.5 hours setting up her sewing machine and making one hat. The total amount of time spent making hats can be represented by the sequence below. 1.5, 2.25, 3.0, 3.75, ...

How many times smaller is the volume of a cylinder if the diameter is multiplied by 1/2

What is 3w (p + 18) equal?

Which of the following are the measurements of the sides of a right triangle? a. 7, 14, 16 b. 6.2, 13.8, 20 c. 10, 11, 13 d. 9, 12, 15

A candidate for mayor promises to reduce property taxes in the city by 2% per year while in office. Suppose the average citizen paid about $9000 per year in property taxes before the election.