The single number 21050 does not define a sequence.
250, 1250, 6250
50
100 200 20
500 contains 50 multiples of 10.
50-10=40. 40+60=100. 100-10=90. 90+60=150. I think we see the pattern. Next number is 150-10 or 140.
Since 10 is a multiple of 5, all multiples of 10 will also be multiples of 5. Test the theory. 30, 50, 100... All multiples of 10, and also of 5.
10 ,20 ,30 ,40 ,50
what number is next in the sequence: 10,20,30,20,(? 30
35 and 70 both have 7 and 5 as prime factors
There are fifty. 50 x 10 = 500
10
4 and 8 are multiples of 2. 6 and 9 are multiples of 3. 40 and 50 are multiples of 10.
There are three numbers between 10 and 50 which are divisible by both 3 and 5. All numbers that are multiples of 3 and 5 are the multiples of the lowest common multiples (lcm) of 3 and 5 which is 15. The multiples of 15 between 10 and 50 are {15, 30 and 45}, thus there are 3 numbers.