since there is a fraction for red markers, we will use the denominator number as total number of red markers in units
red markers total → 3u blue markers total → 200
red markers gave → 2u blue markers gave → 60
red markers left → 3u - 2u = 1u
blue markers left → 200 - 60 = 140
red + blue left → 1u + 140
"she had 180 markers left"
red + blue left → 180
1u +140 = 180 1u = 180 - 140 = 40
3u (red markers total) → 3 x 40 = 120
total markers at first → 200 + 120 = 320