Red and grey bricks were used to build a decorative wall. the number of red bricks/number of grey bricks was 5/2. there were 140 bricks used in all. how many red bricks were used? 20 40 100 28

To find the number of red bricks used, you can create a part to part to whole ratio from the simple ratio of red to grey brick they give.

Then, use the total to create an equivalent ratio with the actual total number of bricks (140).

5 red     100 red
2 grey =  40 grey
7 total   140 total

Each time, the simple ratio was multiplied by 20 to get the actual totals for each color.

There were 100 red bricks used.