Question

In a marbles game, Noah wins $15$ marbles in the first round, but in the next round, she loses $8$ marbles. How many marbles Noah has finally ?

• A. $23$
• B. $-7$
• C. $7$
• D. None of the above

Answer 1

The correct option is C $7$

Number of marbles Noah wins in the first round $=15$
Number of marbles Noah loses in the second round $=8$

$\therefore$ Number of marbles Noah has finally $=15-8=15+(-8)$

Here, we can see that signs of both integers are different. So, to calculate $15+(-8)$, we follow the below steps:

Step 1: Write absolute values of both the integers
$|15|=15|-8|=8$

Step 2: Subtract the absolute values
$15-8=7$

Step 3: Put the original sign of the larger absolute-valued number to the answer

In $15+(-8)$, $15$ has larger absolue value, and the original sign of $15$ is positive. So, we put positive sign to the difference, i.e., $15+(-8)=+7=7$

Therefore, Noah has in-total $7$ marbles finally.

$\therefore$ Option (c.) is the correct one.