Bunuel
Tough and Tricky questions: Geometry.
How many two-digit whole numbers yield a remainder of 3 when divided by 10 and also yield a remainder of 3 when divided by 4?
A) One
B) Two
C) Three
D) Four
E) Five
We need to determine how many two-digit whole numbers yield a remainder of 3 when divided by 10 and also yield a remainder of 3 when divided by 4. Let’s list out the numbers that have a remainder of 3 when divided by 10.
Remainder of 3 when divided by 10:
13, 23, 33, 43, 53, 63, 73, 83, 93
Of those numbers, only 23, 43, 63, and 83 leave a remainder of 3 when divided by 4.
Alternate Solution:
Note that for a number to yield a remainder of 3 when divided by 10, the unit digit must be 3. Note also that for a number to yield a remainder of 3 when divided by 4, three less than that number must be divisible by 4. Combining these two pieces of information, we need to look for two-digit numbers that are divisible by 4 and that have a units digit of zero. These numbers are 20, 40, 60, and 80. Therefore, 23, 43, 63, and 83 are the only two-digit numbers that yield a remainder of 3 when divided by 4 and by 10.
Answer: D