How many numbers between 400 and 700 are divisible by 5, 6 and 7?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 2.
L.C.M of 5, 6 and 7 = 210
The first number divisible by 210 between 400 and 700 is 420.
The last number divisible by 210 between 400 and 700 is 630.
Tn = a + (n - 1) × d
here, Tn = Number of terms, a = first term, d = common difference
⇒ 630 = 420 + (n - 1) × 210
⇒ 210 = (n - 1) × 210
⇒ (n - 1) = 1
⇒ n = 2