I need help

#1
Hi, ( I need help please with this question, however, I showed my effort below. thanks)

about 70%of all US household have a cellular phone. suppose you are conducting a survey of customer satisfaction regarding cellular phones. If you called 20 households selected at random. what is the probability that:

1) everyhousehold has a celllar phone?
binompdf( 20,0.70,20) = 0.000798

2) between seven and twelve households have a cellular phone?

I am clueless here:
I am thinking: binompdf ( 20,0.70,8)
( 20,0.70,9)
( 20,0.70, 10)
(20,0.70, 11)

any feedback is highly appreciated.

Katerine