The chips cost $0.50 a bag and he buys them 5 days a week so that's .50*5 = $<<0.50*5=2.50>>2.50 a week
If he spends $2.50 on chips a week then over 4 weeks he will spend 2.50*4 = $<<2.50*4=10.00>>10.00 on chips
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