Its 30 you find the unit rate by 21÷7 which equals 3 then you multipy 3x10 which gives you 30
Answer:
a
Step-by-step explanation:
Converting all to improper fractions
31/10s = 31/5
5×31s=31×10
155s = 310
s=310/155= 2
20/9=-4/5m
5×20=-4×9m
100=-36m
m=100/-36 = 72 28/36 = 72 7/9
-14/5=-7/2n
-14×2=5×-7n
-28=-35n
n =-28/-35
n=28/35