Your coin collection contains 50 1949 silver dollars. Your grandparents purchased them for their face value when they were new. These coins have appreciated at a 7.6 percent annual rate. How much will your collection be worth when you retire in 2020?

The collection is worth $4,535.35

Explanation:

Giving the following information:

Your coin collection contains 50 1949 silver dollars. These coins have appreciated at a 7.6 percent annual rate.

According to the internet, the 1949 silver dollar had a face value of half a dollar.

We need to use the following formula:

FV= PV*(1+i)^n

PV= 50*0.25= $25

n= 71

i= 0.076

FV= 25*(1.076^71)= $4,535.35

ans.

heterothermic organisms include those organisms that can switch between homeothermic (having body temperature higher than environment) and poikilothermic (having variation in internal body temperature) strategies.

some migratory birds show heterothermy as they decrease their metabolic rate during cold nights to keep their body temperature low. drop in metabolic rate allows increase in production efficiency of birds that reduces the internal body temperature to make it equal to external cold temperature during cold nights.

thus, the correct answer is 'birds allow their temperature drop in order to increase their production efficiency.'

agriculture and oil. natural resources, industry.