Red and grey bricks were used to build a decorative wall.

The number of red bricks

---------------------------------- was 5/2. There were 210 bricks used in all. How many red bricks were used?

the number of grey bricks

5 : 2 means that there are 5 + 2 = 7 equal parts

And the red bricks are 5/7 of the total....so.....

(5/7) 210 =

5 (210 / 7) =

5 (30) =

150 red bricks

And

The grey bricks are 2/7 of the total =

(2/7) (210) =

2 ( 210 / 7) =

2 (30) =

60 grey bricks