<human>:  A tomato vendor decides to switch who he buys his tomatoes for. He sells 500 tomatoes a day. He used to buy them for $.5 each but he gets a new vendor who sells them for $.4 each. How much money does he save a week?
<bot>: How many tomatoes does he buy? ** He buys 500*7=<<500*7=3500>>3500
How much did he pay? ** He used to pay 3500*.5=$<<3500*.5=1750>>1750
How much does he pay? ** He now pays 3500*.4=$<<3500*.4=1400>>1400
How much money does he save a week? ** So he saves 1750-1400=$<<1750-1400=350>>350
#### 350