Answer:
Number of positive four-digit integers which are multiples of 5 and less than 4,000 = 600
Step-by-step explanation:
Lowest four digit positive integer = 1000
Highest four digit positive integer less than 4000 = 3999
We know that multiples of 5 end with 0 or 5 in their last digit.
So, lowest four digit positive integer which is a multiple of 5 = 1000
Highest four digit positive integer less than 4000 which is a multiple of 5 = 3995.
So, the numbers goes like,
1000, 1005, 1010 .....................................................3990, 3995
These numbers are in arithmetic progression, so we have first term = 1000 and common difference = 5 and nth term(An) = 3995, we need to find n.
An = a + (n-1)d
3995 = 1000 + (n-1)x 5
(n-1) x 5 = 2995
(n-1) = 599
n = 600
So, number of positive four-digit integers which are multiples of 5 and less than 4,000 = 600