Four rulers and three pencils cost £2.15 Three rulers and four pencils cost £2.05 Work out the cost of a ruler and the cost of a pencil.

The height of a flare fired from the deck of a ship in distress can be modeled by h(t)= -2(8t^2-52t-28), where h is the height of the flare above water and t is the time in seconds. a. find the time it takes the flare to hit the water.