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Click below to view ALL problems on age Word ProblemsQuestion 185872: Mary, that is sixteen years old, is 4 times as old as her brother. Exactly how old will certainly Mary be when she is double as old as her brother? found 2 options by feliz1965, Fals:Answer by feliz1965(151)
(Show Source): You deserve to put this solution on your website! Mary, who is 16 years old, is 4 times as old together her brother. How old will certainly Mary be once she is double as old together her brother?If mary is 16 and also this is 4 times as old together her brother, climate we deserve to say the her brother is 4 years old.Let M = Mary"s age when she is 2x together old as her brother.16/M = 4/84M = 128M = 128/4M = 32 prize by Fals(5)
(Show Source): You have the right to put this equipment on her website! I"m afraid feliz1965 is wrong and it provides absolutely no feeling to placed an 8 in "16/M = 4/8" or to even use that equation in ~ all. If mary was 32 years old together feliz says, then her brother would certainly be two decades old... 32 is no twice together old as 20.The correct answer is 24. Mary will be 24 year old as soon as she is double the period of her brothers (which will certainly be 12).First, uncover the age of her brother when she is 16 year old:16=4xDivide both sides by 4:4=xSo mar is 16 and her brother is 4.Now we move onto the component where the asks just how old Mary will certainly be as soon as she is twice as old as her brother:16+x=2(4+x)If you don"t recognize why i am utilizing that equation, the is because we room trying to find out how countless years it will take for mar to be twice as old together her brother. Annually Mary and also her brother flourish one year older. Therefore whenever you add a year to mar (x) you must also add a year to her brothers (x). We currently know that mary is 16 year old, and also her brothers is 4 years old. We use 2(4+x) due to the fact that we"re in search of Mary"s age when she is "twice" together old as her brother.16+x=2(4+x)Multiply the 2 by the 4 and also the x:16+x=8+2xSubtract 8 native both sides:8+x=2xSubtract x from both sides:8=xSo now we understand that in 8 year from Mary"s present age (16) she will be twice as old together her brothers (who will also be 8 year older native his present age, i m sorry is 4).
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So currently that we understand x=8 we"ll usage the same equation we started with and plug the 8 in wherein x is:16+x=2(4+x)16+8=2(4+8)Sixteen add to eight amounts to 24, and also four add to eight amounts to 12.24=2(12)So currently we can already see the 24 is double as old together 12.Multiply 2 by 12:24=24In eight years Mary will certainly be 24 and also her brother will be 12. She will be twice as old together her brother once she is 24 years old.16+8=244+8=12