Dan has $ 47. He bought some candy bar for $ 40 each one costing $ 8. How many candy bar did he buy?
Dan has $47. 
He buys candy bars for $40 each. 
Each candy bar costs $8. 

How many candy bars did he buy? 

We can solve this problem by using algebra. We'll set up an equation and solve for the variable. 

We know that Dan has $47, and we know that he spends $40 on candy bars. We also know that each candy bar costs $8. So we can set up the equation: 

47 = 40 + 8x

We can solve this equation by subtracting 40 from both sides. This will give us: 

7 = 8x

We can solve this equation by dividing both sides by 8. This will give us: 

x = 7/8

This means that Dan bought 7/8 candy bars, or 7 candy bars.