21) 7.6
66 – 31= 35% have intake of between 6 and 9 grams per day.
If we assume linearity, 19/35 have between 6 and the median.
19/35 = 0.54
3 x 0.54 = 1.62
6 + 1.62 = 7.62
7.62 ≈ 7.6