The total marks of Charlie increased from 375 to 390 from last year’s result. Find the increase in percentage.

Given: Initial marks of Charlie = 375

Increased marks = 390

Increase in marks = 390 - 375 = 15

∴ Percentage increase in marks

$=\left(\frac{\mathrm{Increase} \mathrm{in} \mathrm{marks}}{\mathrm{Initial} \mathrm{marks}}\right)\times 100$

$=\left(\frac{15}{375}\right)\times 100$

$=4\%$

Therefore, the percentage increase in the marks is 4%.