A metal X is 15 times as donse as matal Z and a metal Y is 8 times as dense as metal Z. In what ratio should these two metals be mixed to get an alloy which is 13 times as dense as metal Z?

Options

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

Answer

D

Explanation

(i) Let the required ratio be x : 1.
(ii) Let the density of metal z be k.
`:. ` Density of metal x = 15 k
Density of metal y = 8k.
(iii) Let required ratio be ` m : 1` .
(iv) (15 k)m+(8k) 1 = (m+1)(13k).
Solve this equation to get m.