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July 25, 2014

July 25, 2014

Posted by **Katherine** on Monday, April 4, 2011 at 6:34pm.

(A) How many postcards did Zachary have in the beginning?

(B) How many postcards did Zachary give to John?

- math !!!! :O -
**Reiny**, Monday, April 4, 2011 at 7:20pmThe way you define your variables is very crucial

let the number of cards John has be 4x

let the number of cards Zach has be 9x

(notice 4x : 9x = 4:9 )

Zach has 45 more than John

so 9x = 4x + 45

5x = 45

x = 9

so now we know that John has 36 and Zach has 81

so after the "give-away"

John has 36+y

Zach has 81-y

we are told that now Zach has 6/7 as many as John

81-y = (6/7)(36+y)

567 - 7y = 216 + 6y

-13y = -351

y = 27

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