1, let the height of trapezoid A be x, bottom 12y and top 6z, then the height of trapezoid B is 2x, bottom 15y, top 9z, trapezoid C is 3x, bottom 10y and top 4z.

The area of a = (12y+6z) * x/2 = x (6y+3z) = 60.

B+C =( 15y+9z)* 2x/2+(4z+ 10y)* 3x/2 = x(30y+ 15z)= 5[x *(6y+3z)]= 5 *。

2.( 1) One for the individual and one for the unit ×275 housing accumulation fund × 12, one year 12 months =6600 yuan.

(2) (1+0.5) × 220×12 = 3960 yuan.

3. Suppose that X buses with 40 seats are rented, and 10 people have no seats; Rent a 50-seat bus y, 10. There are n people in a * * *

Then N = 40X+ 10 = 50Y- 10.

Note that 45× 6 = 270.

So 270

So there are 40×7+ 10=290 people in total.

Checking calculation: 290=6×50- 10, you can take Y=6, which is in line with the proposal.

So there are 290 people.