GMAT Quantitative Reasoning Practice Test 5

Two dung beetles start to run simultaneously towards each other when they’re 150 feet apart. The first beetle runs at a speed of 20 feet per minute and the second beetle runs at a speed of 10 feet per minute. At the moment they start runningtowards each other a fly leaves the first beetle and flies towards the second one at a speed of 70 feet per minute, when he gets there he turns around and starts to fly towards the first beetle and so on. What is the total distance in feet that the fly will travel until the beetles meet?