Two alloys contain tin and iron in the ratio of 1 : 2 and 2 : 3. If the two alloys are mixed in the proportion of 3 : 4 respectively (by weight), the ratio of tin and iron in the newly formed alloy is = ?

• A. 4 : 25
• B. 0 : 21
• C. 2 : 23
• D. 3 : 22