SOLUTION: mary is twice as old as john and half as old as bob.in 2 years times,bob will be twice as old as john.how old is marry?

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Question 893040: mary is twice as old as john and half as old as bob.in 2 years times,bob will be twice as old as john.how old is marry?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Mary is twice as old as john.
m = 2j
and half as old as bob.
m = .5b
or multiply both sides by 2 and you have:
b = 2m
:
in 2 years times, bob will be twice as old as john.
b + 2 = 2(j+2)
b + 2 = 2j + 4
b = 2j + 4 - 2
b = 2j + 2
Replace 2j with m (from the 1st statement)
b = m + 2
replace b with 2m (from the 2nd statement)
2m = m + 2
2m - m = 2
m = 2 yrs is Mary's age