Question

Find Q in the addition.

$31Q+1Q3\underset{–}{}501\underset{–}{}$

• A. 7
• B. 6
• C. 8
• D. 5

Answer 1

The correct option is C

8

Since ones digit of (Q + 3) = 1,
trying all the digits from 0 to 9 we can see that on adding 8 to 3, the ones digit of the sum is 1.
$\Rightarrow$ Q + 3 = 8 + 3 = 11
(1 in ones place of the sum and the other 1 is carried over to the tens place column)

So, the value of Q is 8 and by further proceeding the addition we can verify this.

Now, considering tens place column,
1(carry) + 1 + 8 = 10 (0 in tens place of the sum and 1 carried over to the thousands place column)

Now, considering thousands place column, 1(carry) + 3 + 1 = 5

$318+183\underset{–}{}501\underset{–}{}$