Question

1. ₹ 30 प्रति दर्जन की दर से पेन्सिल बेचने पर दुकानदार को
₹10 का लाभ होता है, तो उसका प्रतिशत लाभ होगा
FINV2011apan​

Answer 1

Magnifying glass is a convex lens of short focal length. It is mounted in a lens holder for practical use.

It is used to see and read the small letters and figures. It is used by watch makers to see the small parts and screws of the watch.