The total number of 4-digit numbers whose greatest common divisor with 54 is 2, is:
Explanation
Solution
Step 1: 54 ka factorization
Humein pata hai ki:
Step 2: Condition samajhna
gcd(n,54)=2 hone ke liye:
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n ko 2 se divisible hona chahiye.
-
n ko 3 se divisible nahi hona chahiye (kyunki agar n, 3 se cut gaya toh gcd kam se kam 2×3=6 ho jayega).
Iska matlab humein aise numbers chahiye jo Even hain par 6 ke multiples nahi hain.
Step 3: 2 se divisible 4-digit numbers nikaalna
Total 4-digit numbers 1000 se 9999 tak hote hain (Total = 9000).
Inmein se 2 se divisible numbers:
n(Divisible by 2)=29000=4500
Step 4: 6 se divisible 4-digit numbers nikaalna
(Jo 2 aur 3 dono se divisible hon):
n(Divisible by 6)=69000=1500
Step 5: Final Calculation
Required numbers = (Total even numbers) - (Even numbers divisible by 3)
Final Answer: