Answer:
85 pens
Step-by-step explanation:
The computation of the number of green pens sold is shown below;
As the number of black pens, red pens, and green pans is 3:5:6
And, the ratio of sold of black pens, red pens, and green pans is 7:3:4
So, the ratio of pens in a number of pens is
= 3 × 7 : 5 × 3 : 4 × 6
= 21: 15 : 24
= 7: 5 : 8
And, the total of 212 pens are sold
So, the number of green pens sold is
= 8 × 212 ÷ (7 + 5 + 8)
= 85 pens