What can be found by counting the number of troughs per second in a wave diagram
amplitude
direction
frequency
speed
wavelength

By counting the number of troughs per second frequency can be calculated.

Explanation:

Frequency of the wave is defined as number of cycles occurring in one second. By counting the number of troughs per second we can calculate frequency of the wave

Amplitude of the wave is defined as maximum displace of the particle from its means position is known as Amplitude.

Wavelength of the wave is defined as distance between two successive  crests or troughs.

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

asthenosphere and convection