A part of monthly

Let the fixed charge be Rs x and the cost of food per day be Rs y.

According to the question,

For Yash,

He took food for 25 days

⇒ x + 25 y = 2200..(i)

For Niyati,

She took food for 20 days

⇒ x + 20 y = 1800….(ii)

Subtract (ii) from (i),

x + 25y – x – 20 y = 2200 – 1800

⇒ 5y = 400

⇒ y = 80

Putting this value in (i),

x + 25× 80 = 2200

⇒ x = 2200 – 2000

⇒ x = 200

Hence, the fixed cost = Rs 200 and the cost for food per day = Rs 80