Which of these would be best explained by the doppler effect? a) the change in frequency as you shorten a guitar string. b) the change in pitch heard as an ambulance approaches you. c) the change in volume as a train pulls away from the station. d) the change in speed of a sound wave as it travels from air into water.

B) The change in pitch heard as an ambulance approaches you.

Explanation:  Don't ask me.

emily ruth's annual premium is $1058.50

step-by-step explanation:

emily ruth is a female of 27 years age purchasing 20 year endowment insurance with face value $25000.

from the given table,

for females, the age of a male 3 years younger should be used.

so, we have to check for 24 year male for 20 year endowment.

it is 42.34 for every $1000 face value.

for a face value of $25000,

it is 25 * 42.34 = $1058.50

∴ emily ruth's annual premium is $1058.50