Answer :
a) 5/100 x 420 = 21
21 x 12 x 3= 756
420 x 12 x 3 = 15,120
15,120+756= 15,876
b) 4/100 x 420= $16.8
21 x 12 x 3= 756
420 x 12 x 3 = 15,120
15,120+756= 15,876
b) 4/100 x 420= $16.8