UKMT Grey Kangaroo, 2015

Geometry Difficulty 2.0 Junior Find the answer United Kingdom

Four identical small rectangles are put together to form a large rectangle as shown. The length of a shorter side of each small rectangle is $10$ cm. What is the length of a longer side of the large rectangle?

(A) $50$ cm (B) $40$ cm (C) $30$ cm (D) $20$ cm (E) $10$ cm

Figure for this problem

We don't reproduce this publisher's solutions. Their own solution is here — work the problem first.

Want a route through all this instead of an archive? The track puts 2,604 problems in a working order, from Junior Challenge level to the IMO shortlist.

Source: UK Mathematics Trust, licensed © UK Mathematics Trust; past papers published free at ukmt.org.uk. Statement reproduced verbatim; metadata (topic, difficulty) added by this project. Solutions are the publisher's, linked not copied.