Question

the number of zeros at the end of N=18!+19!.... please give correct answer

Answer 1

Answer: 20(18!) or 12804731372000000

Step-by-step explanation:

Given: The number of zeros at the end of N $=18!+19!$

Since we know that , $n!=n(n-1)(n-2).............2\cdot1$

Now, the number of zeros at the end of N $=18!+19!$

$=18!+19(18!)\\\\=18!(1+19)\\\\=20\times18!\\\\=20\cdot18\cdot17\cdot16\cdot15..............2\cdot1\\\\= 12804731372000000$

Answer 2

Answer:

18!+19!

we can write 19! as 19×18!

therefore,

18! + 19×18!

18!(1+19)

18!×20

there is 1 zero in 20

and

no.of zeroes in 18! is calculated as....

number of zeroes is due to factor 5×2.

18÷5=3(dont count remainder)

therefore 18! has 3 zeroes

total no. of zeroes 3+1=4