JEE Main 2022 · 30 Jun · Shift 1 · Mathematics Q21

MathematicsInteger+4 / -1Question 21 of 90

The number of 6-digit numbers made by using the digits 1, 2, 3, 4, 5, 6, 7, without repetition and which are multiple of 15 is ______.

Your answer

Answer and worked solution

Official answer: 360

Multiple of 15. Ends in 5; the six digits omit one of 1 to 7 with sum divisible by 3. Total 28, so drop 1, 4 or 7 (not 5).

Count $3\times5!=360$ .

Answer: 360

JEE Main 2022 · 30 Jun · Shift 1, Mathematics question 21