T(value of tractor)= 19000e(-0.255t)+ 1000
Why 1000 makes model 2 more realistic
Tractor always worth at least £1000: value of tractor as scrap metal
Pond observed for one month. By end of month 90% of the surface area of the pond was covered by the weed.
Evaluate the model in light of this information:
Model given suggests pond is fully covered after 20 days 17 hours. Observed data inconsistent as pond is only 90% covered by end of one month.
Hence the model is not accurate
Limitation of model( value of car)
Other factors affect price such as condition/mileage
If the car has had an accident it will be worth less than the model predicts
The price may go up in the long term as it becomes rare
Ethanol has a boiling point of approximately 78C.
Use this information to evaluate the model.
Maximum temperature is 69.6C
Temperature = 69.6 - 51.6e(-0.07t)
Uniform rod assumption
Uniform - mass acts as midpoint of plank
Rod - plank is rigid, doesn’t bend
Area of rhombus/kite
Half the product of the two diagonals
Area of a parallelogram
Base x perpendicular height
Later it was discovered that the local scout group visited the supermarket that afternoon to buy food for their camping trip.
Comment on the validity of the model used to obtain the answer to part e, giving a reason for your answer.
Requires the 20 customers to be a random sample or independent and the members of the scout group may invalidate this, so binomial distribution would not be valid
