Answer:
C. 4.76
Explanation:
20 - 15.24 =
20 - 15 and then you still need to subtract 0.24
20 - 15 = 5
5 - 0.24 just for fun... if it was minus 0.25 then you would know the answer by heart, right, but in that case, you would have subtracted 0.01 too much. So if you add that 0.01 you can do it all by heart,
5 - 0.24 = ( 5 - 0.25 ) + 0.01
( 4.75 ) + 0.01
4.76