How many two-Digit numbers are divisible by 5 ?
Two-digit numbers divisible by 5 are 10,15,20,25 …………………95
We note that here the common difference(d) is 5.
Here the sequence is in arithmetic progression.
We can take a = 1 0 , d = 5 , l = 9 5
∴ `"a"_"n"` = a + (n − 1) d,
9 5 = 1 0 + (n − 1) 5,
n − 1 = 85/5,
n − 1 = 1 7,
n = 1 8.
Hence 18 two-digit numbers are divisible by 5.
We note that here the common difference(d) is 5.
Here the sequence is in arithmetic progression.
We can take a = 1 0 , d = 5 , l = 9 5
∴ `"a"_"n"` = a + (n − 1) d,
9 5 = 1 0 + (n − 1) 5,
n − 1 = 85/5,
n − 1 = 1 7,
n = 1 8.
Hence 18 two-digit numbers are divisible by 5.
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