can someone please answer these questions with working out?
1)If 100g of a substance decays to 80g after 3 years, find, to 1 decimal place,
a) its mass after 10 years
b) the rate of decay after 10 years
c) when it will decay to 50 g
2) Water is flowing out of a pool at the rate given by R=20t liters per minute. If the volume of water in the pool is initially 8000L, find
a) the volume after 5 minutes
b) how long it will take to empty the pool
3) The rate at which an epidemic of measles in a certain city is spreading is proportional to the number of people with measles. That is, dp/dt = kP. If 40 people initially have measles and after 10 days, 110 have measles , find
a) the value of k to 3 sig fig
b) how many people will have measles after 6 weeks.
c) after how long, to the nearest day, 300 people will have measles
d) the rate at which the disease will be spreading after i) 10days ii) 6 weeks
4) A certain chemical reaction treatment of blue green algae in a river causes it to decrease at a rate proportional to the amount of blue green algae in the river. If 250kg after blue green algae reduces to 150kg after 3 months, find how long it will take, to the nearest month, to reduce the blue green algae to 20kg.
1)If 100g of a substance decays to 80g after 3 years, find, to 1 decimal place,
a) its mass after 10 years
b) the rate of decay after 10 years
c) when it will decay to 50 g
2) Water is flowing out of a pool at the rate given by R=20t liters per minute. If the volume of water in the pool is initially 8000L, find
a) the volume after 5 minutes
b) how long it will take to empty the pool
3) The rate at which an epidemic of measles in a certain city is spreading is proportional to the number of people with measles. That is, dp/dt = kP. If 40 people initially have measles and after 10 days, 110 have measles , find
a) the value of k to 3 sig fig
b) how many people will have measles after 6 weeks.
c) after how long, to the nearest day, 300 people will have measles
d) the rate at which the disease will be spreading after i) 10days ii) 6 weeks
4) A certain chemical reaction treatment of blue green algae in a river causes it to decrease at a rate proportional to the amount of blue green algae in the river. If 250kg after blue green algae reduces to 150kg after 3 months, find how long it will take, to the nearest month, to reduce the blue green algae to 20kg.
