Answer: 94.8 % (approx)
Step-by-step explanation:
Let the total household in the U.S is x,
⇒ The total household who did not have a telephone in 1960 = 21.5 % of x
= 0.215 x
According to the question,
The total household who do not have a telephone in 1990 = 75.8 % less than the household in 1960 who did not have the cell phone,
= (100-75.8)% of 0.215x
= 24.2 % of 0.215x
= 0.05203x,
⇒ The household in 1990 who had a telephone = x - 0.05203x = 0.94797x
Hence, the percentage of household who has a telephone in 1990
=
=
⇒ Around 94.8% household had telephone in the US in 1990.