Question

How many numbers up to 400 which is divisible by 3,7 both

Answer 1

Answer:

Numbers which are divisible by 3 and 7 upto 400 = 19

Step-by-step explanation:

Numbers divisible by both 7 and 3 are divisible by 21.

Therefore, using Arithmetic Progression,

first no=21

last number=399

difference=21

Aₙ= a+ (n-1)d

399=21+(n-1)21

19=1+n-1

n=19

Therefore 19 numbers are divisible by both 3 and 7 up to 400.

Hope this helps!