小六數學試題

AB+C=50 ==> 10A + B + C = 50 ..... (1)

CA+B=41 ==> 10C + A + B = 41 ..... (2)

BC+A=77 ==> 10B + C + A = 77 ..... (3)


(1) - (2) ==> 9A - 9C = 9 ==> C = A - 1
(1) - (3) ==> 9A - 9B = -27 ==> B = A + 3

(2) : 10(A-1) + A + (A+3) = 41
12A - 7 = 41
12A = 48
A = 4

B = A+3
= 4+3
= 7

C = A-1
= 4-1
= 3

A=4
B=7
C=3

因 C 是個位 , A 是4