A bag contains 3 red marbles and 4 blue marbles. A marble is taken at random from the bag and replaced. Another marble is taken from the bag. Work out the probability that two marbles taken from the bag are the same colour. Give your answer as a fraction.

Stefano accidentally dropped his sunglasses off the edge of a canyon as he was looking down. the height, h(t), in meters (as it relates to sea level), of the sunglasses after t seconds, is shown in the table. during its descent, the pair of sunglasses passed by a climber in the canyon 6 seconds after stefano dropped them. to the nearest meter, what is difference in elevation between stefano and the climber? 166 meters 176 meters 230 meters 240 meters its b.176 i took the test 166 is wrong and 176 is correct