She needs 8 daisies.
1 arrangement = 10 flowers = 2/10 are daisies.
4 * 10 = 40 flowers
2/10 * 40 = 80 / 10 = 8 daisies.
4 arrangements = 40 flowers = 8/40 are daisies
Proportionality: where a/b = c/d
a = 2 daisies
b =10 flowers
c = 8 daisies
d = 40 flowers
We will know if the proportions are correct because the cross products will be equal.
ad = bc
2*40 = 10*8
80 = 80
