You don't say whether "Drew spend $3/week" means $3/week on things other than the video game. I will assume this is what you meant.
Jan's available $ to apply towards buying the game is $10-$4 = $6/week.
Drew's is $8-$3 = $5/week
Seems that something's wrong here. Together, Jan and Drew have $11 per week to spend on the game. If the game is only $5.50. then Jan and Drew together can buy it after 1/2 a week. But if you meant $55, then Jan and Drew together can buy it after ($55/$11), or 5, weeks.