Answer :
If Blake sold 35 boxes of cookies. Roxie sold 21 boxes and Amy sold three times as many as Roxie and Blake combined. Amy sold 111 boxes of cookies.
It is given,
that Blake sold boxes of cookies = 35
and Roxie sold boxes of cookies = 21
Amy sold 3 times as many as Roxie and Blake combined
so number of cookie boxes Amy sold = 3 × ( number of cookie boxes Blake sold + number of cookie boxes Roxie sold)
putting the values,
number of cookie boxes Amy sold = 3 × (35 + 21)
= 111
thus, Amy sold 111 boxes of cookies.
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(complete question)
Blake sold 35 boxes of cookies. Roxie sold 21 boxes Amy sold three times as many as Roxie and Blake combined. How many boxes of cookies did Amy sell?