1. ## Algebra writing equations

Taken from practise exam:

QUESTION SIX
Peter has more than twice as many CDs as Mary.
Altogether they have 97 CDs.

Write a relevant equation, and use it to find the least number of CDs that Peter could have.

Least number of CDs that Peter could have =

Please explain how I would write an equation to make sence of this. I don't have a clue.

Thanks
Sean

2. Originally Posted by Sean.A.C
Taken from practise exam:

QUESTION SIX
Peter has more than twice as many CDs as Mary.
Altogether they have 97 CDs.

Write a relevant equation, and use it to find the least number of CDs that Peter could have.

Least number of CDs that Peter could have =

Please explain how I would write an equation to make sence of this. I don't have a clue.

Thanks
Sean
Let Peter's amount of CDs = $\displaystyle x$
Let Mary's amount of CDs = $\displaystyle y$

Peter has more than twice as many CDs as Mary
$\displaystyle y > 2x$ --- (1)

Altogether they have 97 CDs
$\displaystyle x + y = 97$

Set $\displaystyle x = 97 - y$ into ---(1)

$\displaystyle y > 2(97 - y)$

$\displaystyle y > 194 - 2y$

$\displaystyle 3y > 194$

$\displaystyle y > 64 \ CDs \ (Approx.)$

Peter should have at least 65 CDs.