<PRE><B>Question 884609</B>
Total number of cookies = 20 * 12 = 240
P + C = 240
P = 2C (The students sold half as many chocolate chip cookies as peanut butter cookies.)
Substitute the value of P from the bottom equation into the top
P + C = 240
(2C) + C = 240
3C = 240
Divide each side by 3
C = 80
.
If 80 chocolate chip cookies were sold, and twice as many PB were sold, then PB = 80 * 2, or 160</PRE>