This year, the number of regional participants increased by 40%, and the number of regional participants was 1+40%.

Girls account for a quarter of the total number, (1+40%)× 1/4.

Last year, girls accounted for one fifth of the total last year. 1/5.

If you subtract last year from this year, you need to multiply the percentage by 100%.

[( 1+40%)× 1/4- 1/5]× 100%=[0.35-0.2]× 100%= 15%

A: Compared with last year, the number of female contestants increased by 15% this year.