Question

The product of two successive integral multiples of 5 is 300. Then the numbers are:

Options

• 25, 30

• 10, 15

• 30, 35

• 15, 20

Answer 1

15, 20

Explanation:

Let the consecutive integral multiple be 5n and 5(n + 1) where n is a positive integer.

According to the question:

5n × 5(n + 1) = 300

⇒ n² + n – 12 = 0

⇒ (n – 3) (n + 4) = 0

⇒ n = 3 and n = – 4

As n is a positive natural number so n = – 4 will be discarded.

Therefore the numbers are 15 and 20.