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Math Snap
PROBLEM
7. The population of a town, P(t), is modelled by the function P(t)=6t2+110t+3000, where t is time in years. Note: t=0 represents the year 2000. a) When will the population reach 6000 ? b) What will the population be in 2030?
STEP 1
1. The function P(t)=6t2+110t+3000 models the population of the town over time. 2. t=0 corresponds to the year 2000. 3. To find when the population reaches 6000, we need to solve for t when P(t)=6000. 4. To find the population in 2030, we need to evaluate P(t) at t=30.
STEP 2
1. Solve for t when P(t)=6000. 2. Evaluate P(t) at t=30.
STEP 3
Set the population function equal to 6000 to find when the population reaches this number: P(t)=6t2+110t+3000=6000
STEP 4
Subtract 6000 from both sides to set the equation to zero: 6t2+110t+3000−6000=06t2+110t−3000=0
STEP 5
Solve the quadratic equation 6t2+110t−3000=0 using the quadratic formula t=2a−b±b2−4ac, where a=6, b=110, and c=−3000. Calculate the discriminant: b2−4ac=1102−4×6×(−3000)=12100+72000=84100
STEP 6
Calculate the roots using the quadratic formula: t=2×6−110±84100t=12−110±290Calculate the two possible values for t: t1=12−110+290=12180=15t2=12−110−290=12−400=−3100Since t represents time in years and cannot be negative, we discard t2.
STEP 7
To find the population in 2030, calculate t for the year 2030. Since t=0 corresponds to the year 2000, t=30 corresponds to the year 2030. Evaluate P(t) at t=30: P(30)=6(30)2+110(30)+3000
SOLUTION
Calculate P(30): P(30)=6(900)+3300+3000=5400+3300+3000=11700The population will reach 6000 in the year 2000+15=2015. The population in 2030 will be 11700.