Answer:
Esmeralda has enough music left in her playlist for a 30 minute workout
Explanation:
we know that
If Esmeralda accidentally deleted 25% of the music, then the percentage of music left in her playlist equals 100%-25%=75%.

Find out how many minutes represent 75% of 40 minutes
Multiply 40 by 0.75

therefore
Esmeralda has enough music left in her playlist for a 30 minute workout