Question 1109036: Annabelle is y^2 years old and her daughters Sarah is y years old. If Annabelle lives to the age of 13y, Sarah will be y^2 years old. How old is Sarah now?
Answer by ikleyn(52865)   (Show Source):
You can put this solution on YOUR website! .
According to the first part of the condition, Anabelle is (y^2 - y) years older than Sarah.
According to the second part of the condition, Anabelle is (13y - y^2) years older than Sarah.
Actually, these two differences are the same:
y^2 - y = 13y - y^2.
Solve it:
2y^2 - 14y = 0
2y(y-7) = 0.
The only meaningful solution to the problem is y = 7.
Answer. Sarah is 7 years old now.
Anabelle is 49 yers old now.
The differences in ages are: 1) 49-7 = 42; b) 13*7 - y^2 = 91-49 = 42.
! Correct !
Solved.
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- Really intricate age word problem
- Selected age word problems from the archive
- Age problems for mental solution
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The referred lessons are the part of this online textbook under the topic "Age word problems".
Save the link to this online textbook together with its description
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