If they both have 1 week's allowance before they spend their money, then the math is like so:
Drew - 8w - 3w = y, where x is $/wk earned and y is $/wk spent and y is $ remaining (8-3)w = y 5w = y This is 1 week, so: 5(1) = y 5 = y
Jan: 10w - 4w = y, where x is $/wk earned and y is $/wk spent and y is $ remaining (10-4)w = y 6w = y This is 1 week, so: 6(1) = y 6 = y
In one week -
Otherwise they are in debt and should learn to hide out until they earn their allowance. Hopefully also learning to live within their means, because the repercussions are usually awful.