SAT Math Multiple Choice Practice Question 380: Answer and Explanation

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Question: 380

6.

In the correctly worked addition problem above, each letter represents a different nonzero digit. What is the value of 2R + T?

A. 4
B. 5
C. 10
D. 11
E. 13

Correct Answer: D

Explanation:

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.)

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