SOLUTION: Maggie’s brother is 7 years younger than four times her age. the sum of their ages is 68 how old is Maddie?

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Question 1121638: Maggie’s brother is 7 years younger than four times her age. the sum of their ages is 68 how old is Maddie?
Answer by MathLover1(20850) About Me  (Show Source):
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let's Maggie’s age be x and her brother's age y
if Maggie’s brother is 7 years younger than four+times her age, we have
y=4x-7....eq.1
if the sum of their ages is 68, we have
x%2By=68.....eq.2

substitute y from eq.1 in eq.2
x%2B4x-7=68
5x=68%2B7
5x=75
x=75%2F5
x=15
so, Maddie is 15 years old
and her brother is:
y=4x-7=>y=4%2A15-7=>y=60-7=>y=53