wa c/s ratio

(September 2016, Q2) A company makes and sells product X and product Y. Twice as many units of product Y are made and sold as that of product X. Each unit of product X makes a contribution of $10 and each unit of product Y makes a contribution of $4. Fixed costs are $90,000. What is the total number of units which must be made and sold to make a profit of $45,000? A 7,500 B 22,500(Answer) C 15,000 D 16,875 I can answer this question correctly. Just take the fixed cost plus profit and divided by the WA C/S ratio. ($90,000+$45,000)/6=$22,500 BUT.......................this rule seem like does not apply to question below. [Extract from examiner report March2019 Example 1] A company makes two products with the following characteristics: Product X Product Y Contribution to sales ratio 0.3 0.5 Selling price per unit $3.00 $4.80 Maximum demand 8,000 units 3,000 units Fixed costs are $9,000. What is the minimum revenue required for production to break even? A $20,400 (True answer) B $25,800 C $29,400 D $24,000 (My answer) If I follow the above rule, i will get $24,000 ($9,000/0.375). I did read the examiner report and i just wonder what makes these two questions different.