Question

How many natural numbers between 101 and 999 are divisible by both 2 and 5

Answer 1

Answer:

89

Step-by-step explanation:

a = 110 {first number to be divided by 2 and 5}

difference d =10

an=990  {last no to be divided by 2 and 5}

an = a + {n - 1}d

990 = 110 + 10n -10

880 + 10 = 10n

890 = 10n  

n = 89

∴ number of natural numbers between 101 and 999 is 89.

Answer 2

Answer:

The answer is 199

Step-by-step explanation:

As the number between 101 and 200 which is divisible by 2 and 5 are 20

That is 105 ,110 ,115,120,125.....

In this way there are 20 in between 101 and 200

So ther will be 200 in 101 and 1000

But we need to find only between 101 and 999

Then it will be 199 as 1000 is also divisible by 2 and 5