This rectangular patio is tiled using 50 cm by 50 cm square tiles. How many tiles are used?

60 tiles

Step-by-step explanation:

First, I would convert cm to m to make it easier

50 cm is .5 m

Now we can find how many tiles across it takes to make one row (5m)

.5 goes into 5, 10 times

That means we need 10 tiles across to fill one row

Now we need to find how many tiles it takes to fill up a column (3m)

.5 goes into 3, 6 times

It takes 6 tiles to fill up a column

Now we know it takes 10 tiles across and 6 vertically

10x6=60

60 tiles

just sum

10 + 10 = 20