Respuesta :
Answer:
3GB’s you just add 21 to 3 and keep adding 3 until you reach 30
21+3=24 24+3=27 27+3=30
Step-by-step explanation:
joe can only use 3gb of data . bill is 21
21+9+30
1gb=3
3*9=9
3(3)+21=30
3×3=$9
$21+9= $30
he can download up to 3 gbs anymore and he'll go over budget.