Aptitude Day 91

Ratio and Proportion:

1. An alloy is to contain copper and lead in the ratio 3:5. The required to be melted with 27 kg of copper is:

Solution:

               Let the required lead to be melted be x.

               3:5 :: 27:x

               3x = 5*27

               x = 45.  

2. 40 kg of an alloy X is mixed with 90 kg of alloy Y. If alloy X has zinc and tin in the ratio 2:3 and alloy Y has tin and lead in the ratio 4:5, then the amount of tin in the new alloy is :

Solution:

                Let the amount of tin in the new alloy be a.

                Amount of tin in X and Y:

                (40/5)*3 = 24. (In alloy X)

                (90/9)*5 = 50. (In alloy Y)

                a = 24+50

                   = 74.