A store sells small notebooks for $7 and large notebooks for $14. If a student buys 6 notebooks and spends $70, how many of each size did he buy?
The student bought 4 small notebooks and 2 large notebooks.
WRONG AGAIN!
4 smalls + 2 large
= 4(7) + 2(14) = 56 , not 70
setup:
number of smalls --- x
number of large ---- y
x + y = 6
7x + 14y = 70 ----> x + 2y = 10
most can solve these in their heads to get
y = 4 and x = 2
check: 2 smalls and 4 large , (the bot had it the other way around)
= 2(7) + 4(14) = 14 + 56 = 70