Correct Answer - Option 5 : 5

**Given:**

15 men can complete the work in 20 days

**Concept used:**

Equating the total work

**Calculation:**

Let the total work be 15 × 20 = 300

Let n be the working days of 15 men

300 = 15 × n + (14 – n) × 25

⇒ 300 = 15n + 350 – 25n

⇒ -10n = - 50

⇒ n = 5

**∴**** The number of day after which 10 men joined the work is 5 days.**