Multiples of 8:
32, 40, 48, 56, 64, 72, 80, 88, 96
{ 30,31,32,....,100 }
How many numbers in the above set are divisible by 8 ?
a. 9
b. 10
c. 11
d. 12
e. 13
please answer and explain
2 answers
only 1 in 8 will be divisible, so divide by 8.
(100-30+1)/8 = 8.8
so, there appear to be only 8 multiples of 8 in that set.
But, the non-multiples on either end take up some of the candidate spots. So, start just after the smallest multiple of 8:
(100-31)/8 = 8.6
So, there are 8 multiples of 8 between 33 and 100, as well. Add in 32, and we have 9 altogether:
32 40 48 56 64 72 80 88 96
(100-30+1)/8 = 8.8
so, there appear to be only 8 multiples of 8 in that set.
But, the non-multiples on either end take up some of the candidate spots. So, start just after the smallest multiple of 8:
(100-31)/8 = 8.6
So, there are 8 multiples of 8 between 33 and 100, as well. Add in 32, and we have 9 altogether:
32 40 48 56 64 72 80 88 96