Question 1150830: Mike age is two third of jake’s age. If the sum of their age is thirty years, how old is jake? Found 2 solutions by ankor@dixie-net.com, greenestamps:Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! m = Mike's present age, j = Jake's
write an equation for each statement
:
Mike age is two third of jake’s age.
m = j
If the sum of their age is thirty years,
m + j = 30
replace m with j j + j = 30
multiply by 3
2j + 3j = 90
5j = 90
j = 90/5
j = 18 is Jake's age
:
:
Check in the first statement; (Mike is 12 obviously)
12 = *18
One clear way to set up the problem directly from the given information, as the other tutor did, is to let j be Jake's age, and so Mike's age is 2/3 of j. Then form an equation that says the sum of their ages is 30 and solve the equation to find Jake's age.
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Since many people (and not just beginning students) prefer to use a setup that avoids using fractions, here is an alternative method for solving the problem.
"Mike is 2/3 of Jake's age"
--> the ratio of their ages is 2:3
--> let 2x be Mike's age and let 3x be Jake's age
Now write and solve an equation that says the sum of their ages is 30:
The disadvantage to this method is that solving the equation doesn't directly give you the answer to the question. The answer to the question is Jake's age, which is 3x = 18.
