if a+b=110 and b=a+100 how much is a? can you pls show me the algerbra workings. thanks!

Question

Just a trivial question when i didn't have a pen to work it out. I know the answer by process of elimination, but I can't show my nephew how I got it. can you please help?

Reagrds

Ben.

Answer 1

a + b = 110;  b = a + 100

a +( a + 100) = 110

2a = 110 -100

2a = 10

a = (10/2)

a = 5