for how many positive integer values of N less than 100 is (N/5) an even integer and (N/4) an odd integer?

Question

the answer choices are ....none, one, two,three,four...

Answer 1

N (N < 100) is a multiple of 10, in which only 20 and 60 satisfies that (N/4) is an odd integer.

Answer 2

For N/5, there are only numbers that end with 5 and 0.
Since we're looking for positive numbers, that eliminates 0 and less that 100 eliminates 100, so

10..... 90 will have 9 values

For N/4 all values will be even, so it will have 0 odd integers

Answer 3

(N/5) = 2a
(N/4) = (2b + 1)
N = 10a
N = 8b + 4
N = 10, 20, 30, 40, 50, 60, 70, 80, 90
N = 12, 20, 28, 36, 44, 52, 60, 68, 76, 84, 92
There are 2 values for N, 20 or 60.