Divide Rs. 21 into two parts so that one is 3/4 of the other. (Ratio and Proportions)

Question

Please Write Steps also, Its From ratio and proportions

Answer 1

Let x and y be the two parts.

 

We know that x + y = 21.

 

x = (3/4)y  one is 3/4 of the other

 

Now use the first equation and substitute the second equation into it.

 

x + y = 21

 

(3/4)y + y = 21

 

Now combine like terms...

 

(7/4)y = 21

 

y = 21/(7/4)   can be re-written as 21/1.75 = 12

 

So if y = 12, look at either equation and substitute in 12 in place of y.

 

What is x?