Answer:
choice 1) 2x + 40 = 180
Step-by-step explanation:
(x + 10) + (x + 30) = 180
2x+ 40 = 180
BD=10 because it is symmetrical to AD.
500 (the current collection) + 10 (the weekly addition) x 20 (weeks to add)
500 + 10*20 (Multiplication comes before addition)
500+200
700
another way I can phrase it
500 total right now
each week he adds 10
after 20 weeks he will have x books
20 weeks=10 times 20 books added=200 books added
500+200=700
answer is 700
