All together, they need to raise ($450 x 6) + $3000 = $<<450*6+3000=5700>>5700
The raised $600 + $900 + $400 = $<<600+900+400=1900>>1900 the first 3 days.
For the next 4 days, they only raised $1900/2 = $<<1900/2=950>>950
In the week, they raised $1900 + $950 = $<<1900+950=2850>>2850
They still need $5700 - $2850 = $<<5700-2850=2850>>2850
Each person still needs $2850/6 = $<<2850/6=475>>475
#### 475