A metal X is 16 times as dense as matal Z and metal Y is 7 times as dense as metal Z . In what ratio should X and Y be mixed to get an alloy12 times as dense as metal Z?

Options

A. ` 2 : 3`
B. ` 5 : 2`
C. ` 5 : 4`
D. ` 6 : 5`

Answer

C

Explanation

(i) Let the required ratio be x : 1 .
(ii) Let the density of metal z be k.
`:. ` Density of metal x = 16 k and that of y = 7k.
(iii) Let the required ratio be m : 1.
(iv) (16k) m+(7k) 1=(m+1) 12k, solve this for m.