Rehana bought a pencil box for Rs. 37.90. If she gave a 50 rupee note to the shopkeeper, how much money did she get back?

Hint- The given problem is a simple arithmetic problem. Rehana gave 50 rupee to the shopkeeper and the cost of the pencil box is 37.90 rupee. So subtract the cost of the pencil box from the 50 rupee note and you will get your answer.

“Complete step-by-step answer:”
Given statement: Rehana bought a pencil box for Rs. 37.90 and she gave a 50 rupee note to the shopkeeper
Money she gave to the shopkeeper $ = Rs.50$
Cost of the pencil box $ = Rs.37.90$
Money she get back =Money she gave to the shopkeeper –Cost of the pencil
$
   = 50 - 37.90 \\
   = Rs12.10 \\
 $
Hence, the shopkeeper returned her $Rs.12.10$

Note- To solve these questions basic arithmetic calculations are needed. Practice as many questions as you can. In this case the number of notes given to the shopkeeper was only one so the money given to the shopkeeper was easy to find. But if there were more numbers of notes then we would have found out the total money given to the shopkeeper by the product of the number of notes and the value of each note.