Answer:
The answer is "
"
Explanation:
Please find the complete question in the attached file.
Using formula:

Given:
put the value into the above-given formula:


1. The wavelength is the ratio of the wave's speed to its frequency in hertz or 1/s. This is shown below,
λ = s / f = (320 m/s) / (300 1/s) = 1.07 m
The wavelength is approximately 1.07 m.
One eighth of a gram will remain
Answer:
0.75 grams
Explanation:
Today we have 6 grams
In 30 years, 3 grams remain
In 60 years 1.5 grams remain
in 90 years 0.75 grams remain
mathematically It would look like this
m = 6(0.5⁽ⁿ/³⁰⁾) where n is number of years
1. It’s true
4 ,7 ,8 is correct