Question

Two alloys contain Beryllium and Aluminium in the ratio of 5 ∶ 6 and 17 ∶ 5 respectively. In what ratio must these two alloys be mixed so that their mixture has equal amount of Beryllium and Aluminium?
1. 3 ∶ 1
2. 4 ∶ 1 
3. 5 ∶ 1
4. 6 ∶ 1 

Answer 1

Correct Answer - Option 4 : 6 ∶ 1 

Given:

The ratio of Beryllium and Aluminium in first alloy = 5 ∶ 6

The ratio of Beryllium and Aluminium in second alloy = 17 ∶ 5

Formula used:

The ratio of the two alloys in the mixture = [(Bigger amount) – (Amount in the mixture)]/[(Amount in the mixture) – (Smaller )]

Calculations:

Amount of Beryllium in first alloy = 5/11

Amount of Beryllium in second alloy = 17/22

Amount of Beryllium in the mixture = 1/2

Using the rule of alligation,

Ratio in the mixture = [(17/22) – (1/2)]/[(1/2) – (5/11)]

⇒ [(17 – 11)/22]/[(11 – 10)/22]

⇒ 6/1

∴ The two alloys will be mixed in the ratio 6 ∶ 1 to have equal amount of Beryllium and Aluminium in the mixture