Word problem

Question

yesterday, mary mailed her wedding invitations. today she mailed 72 more invitations than she did yesterday. if mary mailed 200 invitations in all, how many invitations did she mail yesterday?

Answer 1

N = number she mailed yesterday

 

N + 72 = number she mailed today

 

200 = total number mailed

 

Then

 

N + (N + 72) = 200

2N + 72 = 200

N = (200 - 72) / 2 = 64

 

She mailed 64 invitations yesterday.