so first you add the two ratio, so 4+6 = 10. So now we know that we have 10 parts that we can give out. One part is equal to 50/10 = 5, one part has 5 sweets. so bob gets 4 parts, 4 x 5 = 20 and bill gets 6 parts, 6 x 5 = 30. To make sure you did it correctly , if you add both the number of sweet bill and bob got, u get 20 + 30 = 50, which equals the number of sweets they had in total at the start.