"raise at least $140" tells you that, whatever the variables may be, the french club's profit needs to be 140 or more
they're selling pastries at $3.50 each, so we'll say that p is the number of pastries
140 >/= 3.50p
$140 must be greater than or equal to the profit from sold pastries
then just solve the inequality from there by isolating your variable:
140 >/= 3.50p
divide both sides by 3.50
40 >/= p
so they must sell at least 40 pastries to raise $140 dollars
