AS Physics - Waves

1. Two waves travel with the same speed and have the same amplitude, but the first has twice the wavelength of the second. Calculate the ratio of the intensities transmitted by the waves.

I have: Let the two intensities be Ia and Ib. SO,
Ia=1/r^2 and Ib=2(1/r^2)
So the ratio will be Ia/Ib ; (1/r^2)/(2/r^2)
But if i continue with that i get 1:2, which is wrong. the answer is 1:4

2. A student stands at a distance of 5.0 m from a point source of sound, which is radiating uniformly in all directions. The intensity of the sound wave at her ear is 6.3 x 10^-6 W m^-2.
a) the receiving area of the student's ear canal is 1.5 cm^2. Calculate how much energy passes into her ear in one minute.
So, since I= 6.3 x 10^-6 W m^-2, 6.3 x 10^-6 x 0.015 m^2 = 9.4 x 10^8 W
But now i have no clue how to connect this to time etc.

All help appreciated

1. what is r?

I would attack this problem by saying (for waves in the same medium) intensity is proportional to f² and f is proportional to 1/λ

2.1 Watt = 1 Joule per second

however take care converting areas in cm² to m²
1 cm²is 10^-4 m² not 10^-2