Answer:
She bought 6 bag of chips.
Explanation:
Let the price of bag of chips be s.
Each sandwich cost three times as much as a bag of chips.
Cost of sandwich = 3s
She bought 5 sandwiches for $6.
That is cost of sandwich = 3s = 6
s = 2$
Cost of bag of chips = s = 2$
Price of 5 sandwiches = 5 x 6 = 30 $.
She spent $42, remaining money = 42 - 30 =12 $
Number of bag of chips can be bought with 12 $

She bought 6 bag of chips.