SOLUTION: will a tutor please help me Mary is now twice as old as Jabe.Seven years ago, the sum of their ages was 16.What are their ages now and seven years ago?

Question 30520: will a tutor please help me
Mary is now twice as old as Jabe.Seven years ago, the sum of their ages was 16.What are their ages now and seven years ago?
Mary now-
Jabe now-
Mary 7 years ago-
Jabe 7 years ago-
Found 2 solutions by sdmmadam@yahoo.com, checkley71:
Answer by sdmmadam@yahoo.com(530) (Show Source): You can put this solution on YOUR website!
Mary is now twice as old as Jabe.Seven years ago, the sum of their ages was 16.What are their ages now and seven years ago?
Mary now-
Jabe now-
Mary 7 years ago-
Jabe 7 years ago-
Let Mary be M yrs old now
and let Jabe be J yrs old now
Mary is now twice as old as Jabe
That is M = 2J ----(1)
Seven years ago, the sum of their ages was 16
7 yrs ago
Mary was (M-7) yrs old
and Jabe was (J-7) yrs old.
And then the sum of their ages was 16
Therefore [(M-7) + (J-7)] = 16
M+J -7-7 = 16
M+J-14 = 16
M+J = 16+14
M+J = 30 ----(2)
using(1), M = 2J
2J+J = 30
3J = 30
J = 30/3 = 10
J=10 in (1)
M= 2J = 2X10 = 20
Answer: Mary's present age is 20 yrs
and Jabe's present age is 10 yrs
Seven yrs ago
Mary was (20-7) = 13 yrs
and Jabe was (10-7) = 3 yrs
Verification: The sum of their ages 7 yrs ago is 13+3 = 16 which is correct

Answer by checkley71(8403) (Show Source): You can put this solution on YOUR website!
M+J=16 7 YEARS AGO THEREFORE TODAY THEY ARE EACH 7 YEARS OLDER THUS THEIR COMBINED AGE IS NOW 16+7+7 OR 30.
NOW M=2J THUS M+2M=30 OR 3M=30 OR M=10 & J=20.
MARY IS NOW 10 JABE IS NOW 20.
MARY 7 YEARS AGO WAS 3 JABE 7 YEARS AGO WAS 13.
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