from 2007 to 2012 is only 5 years, so we can see this as a compound interest with a rate of 1.2% per annum for 5 years, so

Answer:
Total number of tables of first type = 23.
Total number of tables of second type = 7
Step-by-step explanation:
It is given that there are 30 tables in total and there are two types of tables.
Let's call the two seat tables, the first type as x and the second type as y.
∴ x + y = 30 ......(1)
Also a total number of 81 people are seated. Therefore, 2x number of people would be seated on the the first type and 5y on the second type. Hence the equation becomes:
2x + 5y = 81 .....(2)
To solve (1) & (2) Multiply (1) by 2 and subtract, we get:
y = 7
Substituting y = 7 in (1), we get x = 23.
∴ The number of tables of first kind = 23
The number of tables of second kind = 7
1. The two equations follow the slope-intercept form which y=mx + b. They have the same y-intercept which is equal to 900.
2. Suppose x= 10
Plan Alpha: y=-7x+900=-7(10)+900=830
Plan Foxtrot: y = -17x+900 = -17(10)+900=730
Between the 2 plans, the lower value is 730. Plan Foxtrot is better for reduction of pollution.
3. The city council should choose Plan Foxtrot because the reduction of pollution is much greater. Their goal would be reached faster if they go with faster reduction of pollution.