Mathematics problem solving:

assume two numbers x and y

the sum of x and y is,x+y=90-------(1)

and also the x is 14 more than three times of y

   x=3y+14

let substitute the value of x in equation (1)

 3y+14+y=90

4y=90-14

4y=76

=>y=19

x=3(19)+14

x=57+14

x=71

Let the numbers be x and y, where x is the larger number.
So according to the given data:
x+ y = 90 
and
x = 3y + 14 
use this value of x in first equation, you will get
3y + 14 + y = 90 
4y = 76
y = 19
Now use the value of y again in the first equation, you will get
x + 19 = 90 
x = 71