In two alloys A and B the ratio of Zinc and Tin is 5 : 2 and 3 : 4 respectively. 7 kg of the alloy A and 21 kg of the alloy B are mixed together to form a new alloy. What will be the ratio of Zinc and Tin tin the new alloy ?

• A. : 1
• B. : 2
• C. : 3
• D. : 1