Question

Find the numbers between 600 to 1000 that are divisible by 7 and 9

Answer 1

multiples of 9 and 7=63 then AP=630,663........945

a=630

d=63

an=945

an=a+{n-1}d

945=630+{n-1}63

945-630={n-1}63

315/63=n-1

5=n-1

n=5+1

n=6

Answer 2

Answer:

There are 6 numbers between 600 to 1000 that are divisible by 7 and 9.

Step-by-step explanation:

To find : The numbers between 600 to 1000 that are divisible by 7 and 9?

Solution :

Number which is divisible by 7 and 9 must be divisible by their multiple i.e.

$7\times 9=63$

The numbers between 600 to 1000 which are divisible by 63 are

630,663........945  which form an A.P.

Where, First term is a=630

Common difference is d=63

Last term is l=945

Applying last term formula,

$l=a+(n-1)d$

$945=630+(n-1)63$

$315=(n-1)63$

$\frac{315}{63}=(n-1)$

$n-1=5$

$n=6$

Therefore, There are 6 numbers between 600 to 1000 that are divisible by 7 and 9.