During a research experiment, it was found that the number of bacteria in a culture grew at a rate proportional to its size. At 9:00 AM there were 3000 bacteria present in the culture. At noon, the number of bacteria grew to 3800. How many bacteria will there be at midnight?

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%.

Solve each quadratic equation by factoring and using the zero product property. 14x - 49 = x^2

Julie buys 2kg of apples and 7kg of pears ? 12.70. the pears cost ? 1.30 per kilogram what is the price per kilogram of the apples? show your working out