Hey guys! 
So today’s problem is this :
Problem on Ratios and Proportions for SSC-CGL 2016
If 3x = 5y = 4z, then x : y : z is equal to ?
a). 9 : 12 :16 b). 20 : 12 : 15
c). 15 : 10 : 9 d). 8 : 5 : 3
Solution :
Okay so now in problems like these, the first thing you do is that you seperate the numbers associated with the variables x,y and z.
So here our numbers are 3, 5 and 4.
Now take an LCM of it. So the LCM of 3, 5 and 4 will be 60.
For your final step, form this equation :
LCM/3 : LCM/5 : LCM/4
60/3 : 60/5 : 60/4
20 :12 : 15
Hence, the answers is (b)
PRO TIP : From the question itself, you can identify that x will be the biggest number, followed by z and then y. So eliminate (a), (c) and (d) and hence (b) is your answer! 😉 Get it ?