SAT Math Multiple Choice Practice Question 380: Answer and Explanation
In the correctly worked addition problem above, each letter represents a different nonzero digit. What is the value of 2R + T?
Correct Answer: D
D Although you were probably taught to add the "rightmost" digits first, here the "leftmost" digits provide more information about the number, so it's best to start there.
The largest possible 3-digit number that can be formed by adding two 2-digit numbers is . Therefore, T must be 1.
Therefore, there must be a "carry" of 1 from the addition of R + S in the 10s column. Looking at the units column tells us that S + R yields a units digit of 4, so . The addition in the 10s column tells us that . (The "+ 10" is needed for the carry into the 100s column.)