Answer:
2 (option B)
Question:
Prajna is listing squares of two-digit numbers in such a way that the digit in their units place is 6.
How many numbers should he have listed?
a) 9 b) 2 c)18 d) 20
Step-by-step explanation:
We would find the perfect squares that are two digit numbers
For two digit perfect squares:
Largest two digit number= 81 = 9²
Smallest two digit number= 16 = 4²
Total Two digit number perfect squares = Highest number - lowest number + 1
= 9-4+1 = 6
There are 6 two digit perfect squares
Next, we have to find how many of them have 6 in their units place.
The rule to be applied: If a number has 4 or 6 in the unit place, then its square has 6 in the units place.
Following this, the possibilities are 4², 6².
We have two of such numbers.
Therefore, he would have listed 2 numbers.
