Question

P and Q are two alloys of aluminum and brass prepared by mixing metals in proportions 7:2 and 7:11 respectively. If equal quantities of the two alloys are melted to form a third alloy R, the proportion of aluminum and brass in R will be :
a) 5:9 b) 5:7 c) 7:5 d)9:5

Answer 1

Given:

P and Q are two alloys of aluminium and brass prepared by mixing metals in proportions 7:2 and 7:11 respectively.

If equal quantities of the two alloys are melted to form a third alloy R

To find:

The proportion of aluminium and brass in R

Solution:

As per the given condition of the question, the two alloys of different ratio of the particular elements are mixed in equal proportion.

So we have to make the sum of the ratio in both solutions equal to each other.

[Alloy A    7           2    ----  9]2

Alloy B    7           11    ----  18

Alloy A    14           4    ----  18

Alloy B    7           11    ----  18

Alloy R    21          15            

So,

The proportion of aluminium and brass in R is 7:5

Hence option (c) is correct

Answer 2

Answer:

option c: 7:5

Step-by-step explanation:

p and q are the alloys of aluminium and brass formed by mixing aluminium and brass in two different proportion (7:2 and 7:11)

if equal amount of p and q are mixed to form R what will be the proportion

p alloy contains total quantity of 9

q contains total quantity of 18

so inorder to take equal amounts we take LCM and mix them together.

by taking LCM both becomes

14:4

7:11. (+) =21:15 = 7:5