The number of bacteria in a petri dish on the first day was 252
cells. if the number of bacteria increase at a rate of 57% per day, how many bacteria cells will there be after 7 days?

The sum of the product of 4 and x and the product of 7 and y is 61. the sum of the product of 12 and x and the product of 21 and y is 61. what are the values of x and y?

Adepartment store purchases screen-printed t-shirts at a cost of $5 per shirt. they mark up the price 150% (making the selling price 250% of the store's purchase price) and put them on the sales floor. every month that a t-shirt doesn't sell, the store reduces the selling price by 25%.

An arc subtends a central angle measuring 7pi/4 radians what fraction of the circumference is this arc?