​X and Y are two alloys of Gold and Platinum prepared by mixing the metals in the ratio of 5 : 2 and 5: 7, respectively. If we melt equal quantities of the alloys to form a third alloy Z , then the ratio of the quantity of Gold to the quantity of Platinum in Z will be:​

Correct option is C

Given:

Gold to Platinum ratio in alloy X = 5 : 2

Gold to Platinum ratio in alloy Y = 5 : 7

Solution:

Gold to Platinum ratio in alloy X =5:2

Total quantity of Gold and Platinum ratio in alloy X = 5+2 =7   …..(1)

Gold to Platinum ratio in alloy Y =5:7

Total quantity of Gold and Platinum ratio in alloy Y = 5+7 =12   ……(2)

Since equal quantity are mixed :

Eq (1) $$\times$$​ 12 and eq(2) $$\times$$​ 7

Then ratio (1) becomes 5 $$\times$$​ 12 : 2 $$\times$$​ 12 = 60 : 24

Then ratio (2) becomes 5 $$\times$$​ 7 : 7 $$\times$$​ 7 = 35 : 49

In the third alloy Z ratio of Gold : Platinum = adding the ratios together

= (60 + 35) : (24 + 49)

= 95 : 73

In alloy Z Gold and Platinum are in ratio 95 : 73