Three brands split a town's toothpaste sales: X has 38%, Y has 34% and Z has 28%. Next year X's share rises by 5 percentage points while Y's share falls by 25%. What will Z's share be?

X becomes 38 + 5 = 43. Y falls by a quarter of itself: $34\times 0.75=25.5$. The three shares must still total 100, so $Z=100-43-25.5=31.5$%. 34.6% reads X's '5 percentage points' as 5% of 38, giving 39.9 and leaving $Z$ with 34.6. 48% reads Y's 25% fall as 25 percentage points, dropping Y to 9. 28% assumes $Z$ is untouched, but a share can move without the brand doing anything - the other two have squeezed the total.