The sum of two numbers is 90. their difference is 18. find the numbers.

A+b=90, let b>a, so b-a=18 

from the first statement b=90-a, using this value of b in the second gives you:

(90-a)-a=18

90-2a=18

-2a=-72

a=36, and since b=90-a

b=90-36=54.  so the numbers are

54 and 36

The question is kind of confusing. if it's asking how many variations of answers can you give. then do 4^5 for your answer.this would be something like the first question could be a and the 2nd c or first b next c etc. if you can, ask the teacher for a better confirmation of what it's asking. if i'm assuming correctly what it's asking, it's 625 different variations.

The answer to your question is b