Question

30 45 75 105 165 ? what will come in palce of question mark?​

Answer 1

Answer:

195

Step-by-step explanation:

Series: 30, 45, 75, 105, 165, ?

Pattern:  Every number is multiple of 15. The multiple is a prime number.

⇒ 15 × 2 = 30

Here, 2 is a prime number.

⇒ 15 × 3 = 45

Here, 3 is a prime number.

⇒ 15 × 5 = 75

Here, 5 is a prime number.

⇒ 15 × 7 = 105

Here, 7 is a prime number

⇒ 15 × 11 = 165

Here, 11 is a prime number.

Hence 15 × 13 = 195

Here, 13 is a prime number.

Hence 195 is the number that must come in the place of question mark.

Answer 2

Given:  A number series-  30, 45, 75, 105, 165, ?

To find: The number that can replace the question mark

Solution:  The given series is:

30, 45, 75, 105, 165, ?

On observing carefully, we find that the given numbers in the series are multiples of 15 and prime numbers starting from 2.

∵ 30 = 15 × 2, where 2 is a prime number

∵ 45 = 15 × 3, where 3 is a prime number

∵ 75 = 15 × 5, where 5 is a prime number

∵ 105 = 15 × 7, where 7 is a prime number

∵ 165 = 15 × 11, where 11 is a prime number

So, the required number will also be a product of 15 and the prime number after 11 i.e., 13

∴ 15 × 13 = 195

Hence, 195 will come in place of question mark.

∴ The series is  30, 45, 75, 105, 165, 195