This is because the constant of proportionality is 7 since 35/5 since it is the ratio for Natasha. Since 7 is the constant of proportionality, you multiply it by the difference of the ratios. In this case, Natasha and Henry have a difference of 1 in ratios. Since it is a difference of 1, you multiply that by the constant of proportionality, 7. 7 X 1 is equal to 7, so Natasha gets 7 more sweets than Henry.
