Answer:
A = $150
B = $130
C = $140
Explanation:
Let the amount received by a be $x
b receives $20 less than a;
we have that;
b = x - 20
c receives half of Sum A and B
c = (x + x-20)/2
c = (2x-20)/2
c = x - 10
Add all and it gives 420
x - 10 + x -20 + x = 420
3x -30 = 420
3x = 420 + 30
3x = 450
x = 450/3
x =$150
a = 150
b = x - 20; 150 - 20 = 130
c = x-10
c = 150-10
c = $140