can you please help me to answer question #4 thanks in advance

() 4. Using your results for the half-life from the previous 2 questions, predict the time required for 3 half lives to have passed (an 87.5% reduction). Explain, using the graph, to justify your answer. BI U XX= The time required for the initial amount to be reduced into half is the half life and that is 180 secs for 137Ba . After one half life remaining amount is 50% Similarly after 2 half lives ( when 75% decomposed) remaining amount is 25% and time required = 180x2 = 360 secs So for 3 half lives time requires = 180x3 = 540 secs And after passing 3 half life the remaining amount is 25/2 = 12.5% and decomposed amount =( 100-12.5)= 87.5% So time requires = 540 secs to pass 3 half lives Score: 0/3@931 1. In this section we will use the data from the videos to determine the half life of barium-137. The half life of a radioactive isotope is the time it takes for some amount of a substance to decay to half of the original quantity. If you start with 10 g of a substance, the half life is the time it takes for only 5 g to remain. The importance of ha lf- life in first- order reactions comes in when you go further, because it takes the same amount of time to lose the rst 50% as it does to lose the next 25%: .5935 Reviewing .................... l]! .2.?.'?smivin9 .................... ................................... 0'!- ; H 1.1: r' 2 - rm The half life is represented by t1 /2 in the graph. '33:}:3' 2- Take a look at your graph. Approximately how long does it take for 50% of the 13730. to decay? [5332' 120 seconds ] O 180 seconds ' 360 seconds ] ' 1000 seconds ]