Hmm. Interesting all the ways to approach it. I must be visual in my math approach. I immediately pictured 25 trays in line as if set on a long table. Starting from the left each tray had a cup and starting from the right each tray had a plate. Then I just looked at how many trays had both=11. My mental picture even included small blue teacups and pink plates like my DD teaset. Weird. Its a wonder I passed calculus.