Translate this word problem as a system of equations and then solve using substitution. The sum of two numbers is 84. One number is three times the other. Find the numbers.

Question

parthkohli · Answer

Well let's take them as x and y.

$\Large \color{Black}{\Rightarrow } x + y = 84$

$\Large \color{Black}{\Rightarrow x = 3y}$

anonymous · Answer

let first number is x
     second number is y
the sum of two numbers is 84
so, x+y=84---- a
x is 3y
x=3y
now put x=3y in eq a
3y+y=84
4y=84
y=84/4
y=21
now as 
x=3y
x=3* 21
x= 63