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Click here to view ALL troubles on period Word ProblemsQuestion 185872: Mary, who is sixteen years old, is 4 times together old together her brother. How old will Mary be as soon as she is double as old as her brother? uncovered 2 services by feliz1965, Fals:Answer by feliz1965(151)
(Show Source): You deserve to put this systems on your website! Mary, that is sixteen years old, is four times together old as her brother. How old will Mary be once she is twice as old as her brother?If mar is 16 and also this is 4 times as old together her brother, climate we deserve to say the her brothers is 4 years old.Let M = Mary"s age when she is 2x as old together her brother.16/M = 4/84M = 128M = 128/4M = 32 answer by Fals(5)
(Show Source): You can put this systems on your website! I"m afraid feliz1965 is wrong and also it makes absolutely no sense to put an 8 in "16/M = 4/8" or to even use that equation at all. If mar was 32 years old together feliz says, then she brother would certainly be twenty years old... 32 is no twice as old as 20.The exactly answer is 24. Mary will be 24 years old when she is double the period of her brother (which will be 12).First, discover the period of she brother once she is 16 year old:16=4xDivide both political parties by 4:4=xSo mar is 16 and her brother is 4.Now we move onto the component where that asks just how old Mary will be when she is twice as old together her brother:16+x=2(4+x)If girlfriend don"t understand why ns am utilizing that equation, it is due to the fact that we are trying to uncover out how many years it will certainly take for mar to be twice as old together her brother. Each year Mary and her brother prosper one year older. So whenever you include a year to mary (x) you need to also add a year to her brothers (x). We already know that mar is 16 year old, and her brothers is 4 year old. We use 2(4+x) since we"re looking for Mary"s period when she is "twice" as old as her brother.16+x=2(4+x)Multiply the 2 through the 4 and also the x:16+x=8+2xSubtract 8 from both sides:8+x=2xSubtract x native both sides:8=xSo currently we know that in 8 year from Mary"s current age (16) she will be double as old as her brother (who will additionally be 8 years older indigenous his current age, which is 4).
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So currently that we understand x=8 we"ll use the exact same equation we started with and plug the 8 in whereby x is:16+x=2(4+x)16+8=2(4+8)Sixteen add to eight equals 24, and four add to eight amounts to 12.24=2(12)So now we can already see that 24 is twice as old as 12.Multiply 2 by 12:24=24In eight years Mary will be 24 and also her brother will be 12. She will certainly be double as old as her brother once she is 24 year old.16+8=244+8=12