there's a grid of squares with 12 rows and in each row there are 15 squares
from this grid she colours 8 squares from each row for 5 rows blue.
the rest of the squares she colours red
so first we have to find how many squares are there in the grid in total
so if each row has 15 squares
then 12 rows have - 15 x 12 = 180 squares
blue coloured squares
she colours 8 rows of 5 squares
so if 1 row has - 5 squares
then 8 rows have - 5 x 8 = 40 squares
from 180 squares, she colours 40 squares blue and the rest red colour
therefore the squares she colours red are
red squares = 180 - 40 = 140 squares
she colours 140 squares red
