the sum of 2 numbers is 45

Question

and "the difference of 2 numbers is 10" and Julia's age is 3 more than twice Kris's age

Answer 1

Let x and y be the two numbers:

• the sum of 2 numbers is 45:  x + y = 45
• the difference of 2 numbers is 10:  x - y = 10

 

x + y = 45

 

so x = 45 - y

 

Substitute 45-y in place of x in the second equation:

x - y = 10

45 - y - y = 10

45 - 2y = 10

35 = 2y

 

17.5 = y

 

Find x:

x = 45 - y

x = 45 - 17.5

x = 27.5

 

You didn't provide enough information on the age problem (Julia and Kris).  Please recheck the problem statement and re-post your question with the missing information.