2 m

R=8+2= 10 (m)

8 meters

3. 14×( 10 -8 )

=3. 14×36

= 1 13.04 m2

(2)10000 * 5 * 3.6% =1800 (yuan)

(3)48÷( 1-8%×0.5)

=48÷96%

=50 kg

(4) 17

(5) Analyze the workload of each group for one day:

A+B = 1/36 (i)

B+C = 1/45 (2)

A+C = 1/60 (3)

(I)+(iii)-(ii)= & gt；

2 * A = 1/36+ 1/60- 1/45 =(5+3-4)/ 180 = 1/45。

= & gtA = 1/90

So a person needs 1/( 1/90)=90 days.

Do the rest yourself.