Question

A and b are two alloys of gold and copper prepared by mixing metals in the ratio 7:2 and 7:11 respectively. If equal quantities of the alloys are melted to form a third alloy c, then the ratio of gold and copper in alloy c will be

Answer 1

OPTION

1) 1:3

2) 3:7

3) 5:9

4) 7:5

5) 2:9

6) 11:18

7) 7:6

8) 5:6

9) 2:5

10)2:3

Solution

Let 1 kg of each one of A and B be taken to form 2 kg of C.

Gold in 1 kg of A = 7/9, copper in 1 kg of A = 2/9

Gold in 1 kg of B = 7/18, copper in 1 kg of B = 11/18

Gold in 2 kg of C = (7/9 + 7/18) = 21/18 = 7/6

Copper in 2 kg of C = (2/9 + 11/18) = 15/18 = 5/6

Ratio of gold and copper in C = 7/6 : 5/6 = 7:5

Option 4)