8 [ ] 3
[] 8 7
5 7 [] +
_______
[] 3 8 6
What is the sum of all the blank numbers?
a. 17
b. 18
c. 19
d. 20
e. 21
I got C because I thought of it as 6+2+9+2. However, it didn’t work. What was missing?
Assuming the equation is of the form 8A3 + B87 + 57C = D386, I got A = 2, B = 9, C = 6, and D = 2 as the only solution. Indeed, 823 + 987 + 576 = 2386, and the sum of the blank numbers is 19. Your definition of “it didn’t work” is probably incorrect, or your answer key is wrong.
Okay, then TCB must be wrong. They said A for some reason.
CB made this error? Is it in their blue book?
No, this is the white 1997 [10 Real SATs book](http://www.amazon.com/10-Real-Sats-Cathy-Claman/dp/0874475678). Its math problems are harder than the blue book’s.
Hmm interesting. And you’re absolutely sure you typed the question correctly? I have seen a few other test prep resources make lots of mistakes, some of them unforgivable to the point that I would boycott those resources.
Yeah I typed it right, but I substituted brackets instead of triangle, circle, and rectangle figures. It looks like 18 years ago TCB was different than what it is now.
CB tends to make mistakes on their math questions as well:
http://www.nytimes.com/1982/05/25/us/error-found-in-sat-question.html
You’d be better off if you only use current materials from the CB
^ In general, I agree. But if you have “used up” the current materials (something I believe hardly anyone really does) then old stuff is better than fake stuff. And as one of the older tutors here, I admit that I am having nostalgia for these old problems – haven’t seen them in a long time. So thumbs up on the deep background prep. But yes, @CHD2013 is right: be sure you have done a thorough job with the current material.