Second, 50 ÷ 6 = 8...2

7×8+2=58

3. The number divided by 6 and less than 2 is: 4, 10, 16, 22, 28 ... (add 6 in turn.

Divided by 7, the number less than 3 is: 4, 1 1, 18, 25 ... (add 7 in turn.

The first number that appears in both columns is 4.

4+42K(42 is the least common multiple of 6 and 7)

These bits are 2 (even number divided by 5).

Then the minimum value of k is 4, so this number is 4+42×4= 172.

4. 1 divided by 4 is: 1, 5, 9, ... 49. There is one in every four numbers.

50÷4= 12 (pieces) ...

12+ 1= 13

1+2+3+.........+49

=( 1+49)× 13÷2

=325

5. Let 69 = a1* x+r; 95 = a2 * x+r； 108=a3*x+r

So x = (95-69, 108-95, 108-69) = 13.

A: This number is 13.

6. The rules are 2, 3, 6, 8, 4, 2, 6, 8, 4, 2 ... So rule 80 is 8.

7. Suppose that one kilogram of apples is X yuan and one kilogram of oranges is Y yuan.

5x+4y=27.2，4x+5y=26.8

9x+9y=54，x+y=6

So x = 3.2 and y = 2.8.

A: One kilogram of apples is 3.2 yuan, and one kilogram of oranges is 2.8 yuan.

8. Let B be X and A be 3x+2.

x+3x+2=62

x= 15

So a is 47 and b is 15.