Sami decided to give Kachoris to her friends on her Birthday. If she gives 3 Kachoris to each friend, one friend will get only 1 Kachori. Also, if she gives 2 Kachoris to each friends, she will be left with 13 Kachoris. How many friends are there? 

Given Data:

By giving 3 kachoris to each friend, one friend receives only 1 kachori.

By giving 2 kachoris to each friend, Sami is left with 13 kachoris.

Concept:

The total number of kachoris is constant. By setting equalities for the total number of kachoris in both scenarios, we can solve for the number of friends.

Solution:

⇒ Let's denote the number of friends as 'f'. We can express the total number of kachoris as {(f - 1) * 3 + 1} which accounts for one friend receiving less.

⇒ If she gives 2 kachoris to each friend, the total becomes {f × 2 + 13} which includes the extra kachoris she is left with.

⇒ Equating these two expressions yields the equation: (f - 1) × 3 + 1 = f × 2 + 13.

⇒ Simplifying this equation leads to 3f - 3 + 1 = 2f + 13.

⇒ f = 15.

Therefore, Sami has 15 friends.