Question #c7676

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Answer 1 · 2017-12-14T23:11:46

#16# (years)

Let #J# equal June's current age and #S# be June's sister's current age. Now we begin:

#J-10 = 0.5(S-10) #

#=> 12J - 120 = 6S - 60#

#=> 12J - 60 = 6S#

and

#J+20=6/7(S+20)#

#=> 7J + 140 = 6S + 120#

#=> 7J + 20 = 6S#

Subtract the bottom equality from the top to get

#5J - 80 = 0#

#=> J = 16#

You can check that this answer is correct by plugging back into the initial equations/relationships that were given.