Question

A square dartboard contains a red square and a blue square that overlap. A dart hits a random point on the board.

Express your probability as a decimal rounded to 2 decimal places.

Answer 1

They want to know the probability of landing in the blue and red section at the same time. In other words, they want to know the probability of landing in the purple section.

We'll need the area of the purple square. This square is 1.5 inches by 1.5 inches. This is because 4 - 2.5 = 1.5

So the purple square has an area of 1.5*1.5 = 2.25 square inches

Divide this over the total area of the largest square (which is 9x9) to get 2.25/81 = 0.02777... where the 7's go on forever

Round that to two decimal places. The final answer is 0.03

Side note: 2.25/81 is equivalent to the reduced fraction 1/36 (express 2.25/81 as 225/8100 and then divide both parts by the GCF 225)