Question 655161
Sahara is3 times as old as rob. Their ages together add up to 16. How old is sahara?  Show me how to write out the equation so i can get the answer. 
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Let s = Sahara's age
and r = Rob's age
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From:"Sahara is3 times as old as rob." we get equation 1:
s = 3r
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From:"Their ages together add up to 16" we get equation 2:
s+r = 16
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Substitute 's' as defined in equation 1 into equation 2 and solve for r:
s+r = 16
3r+r = 16
4r = 16
r = 4 years old (Rob's age)
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Sahara's age:
s = 3r = 3(4) = 12 years old