Question 59953
Let "x" and "y" be two numbers. 


Given that one is thrice the other.


Hence x = 3y.


Given that the sum of their reciprocals equals 4/21 


Thus, the equation is: 


1/(3y + y) = 4/21


1/4y = 4/21 


16y = 21


y = 21/16 


Therefore,  x = 3y 


x = 3(21/16)  


x = 63/16 


Thus the two numbers are x = 63/16 and y = 21/16