Alloy A contains copper and zinc in the ratio 4 : 5 and alloy B contains…
2020
Alloy A contains copper and zinc in the ratio 4 : 5 and alloy B contains copper and zinc in the ratio 7 : 2. A and B are taken in the ratio 7 : 4 and melted to form a new alloy. The percentage of zinc in the new alloy is closest to: (correct to two decimal places)
- A.
43.43%
- B.
47.5%
- C.
45.25%
- D.
47.79%
Attempted by 3 students.
Show answer & explanation
Correct answer: A
In alloy A, zinc fraction = 5/9. In alloy B, zinc fraction = 2/9.
A and B are mixed in the ratio 7:4.
Zinc fraction in the new alloy = (7 x 5/9 + 4 x 2/9)/(7 + 4) = 43/99.
Percentage of zinc = 43/99 x 100 ≈ 43.43%.