⓵ You have to do a cross product in order to find your answer :
1/4 lb → 3 servings
1 ½ lb → × servings
(3 x 1 ½) ÷ 1/4 = (3 x 1,5) ÷ 0,25
⓶ Now you need to solve the equation :
(3 x 1,5) ÷ 0,25
↓
(4,5) ÷ 0,25
↓
4,5 ÷ 0,25 = 18
Which means that your final answer is that Mark can make 18 servings with 1 ½ lb of onions!
I hope this helped! ☻