The sum of two numbers is 18. The difference between three times the lesser number and the greater number is 10.

Question

so confused, help please!

Answer 1

The two equations are x + y = 18 and 3x - y = 10, use elimination or substitution to solve for x and y

Answer 2

Let n be the lesser number, m be the greater number.

 

(i)    n + m = 18

(ii)   3n - m = 10

 

From (i) get

 

n = 18 - m

 

and plug this into (ii).

 

3(18 - m) - m = 10

54 - 4m = 10

4m = 44

 

m = 11

 

Plug this into (i) and get

 

n + 11 = 18

 

n = 7

 

Test the solution.