proszę o pomoc daje naj

a)
6 : 2/3 = 6 * 3/2 = 9
b)
3/8 : 5/4 = 3/8 * 4/5 = 12/40 = 3/10
c)
3 * (7 : 3/5) = 3 * (7 * 5/3) = 3 * 35/3 = 35