Final answer:
The percentage of families who recycled in 1990 is approximately 0.00%.
Step-by-step explanation:
To find the percentage of families who recycled in 1990, we need to substitute the value of t with (1990-1960) in the given function p(t) = 100/1400xe^(-0.15t):
p(1990) = 100/1400e^(-0.15(1990-1960))
= 100/1400e^(-0.15(30))
= 100/1400e^(-4.5)
Using a calculator, evaluate e^(-4.5) to get approximately 0.0111.
Therefore, p(1990) is approximately 100/1400 * 0.0111 = 0.0000079.
To convert this to a percentage, multiply by 100: 0.0000079 * 100 = 0.00079%.
Rounding this to the nearest hundredth, the percentage of families who recycled in 1990 is approximately 0.00%.