It seems that you are trying to find the length of hair of Florencia on Tuesday.
Given that length of the hair of Florencia on Monday = h centimeters
On Tuesday, she got hair cut.
So new length of the hair of Florencia on Tuesday = 75% of Monday value
= 75% of (h)
= 0.75* (h)
= 0.75h
Hence final answer is the length of the hair of Florencia on Tuesday is ( 0.75h ) centimeters.
She posted 2/5 of them
90 times 2/5=180/5=36
she posted 36
90-36=54
she posted 2/3 of remaining (54)
2/3 times 54=108/3=36
54-36=18
she has not yet posted 18 of them
30 + 8 = 38 desks
38 x 4 = 152 legs
If you did not add those eight desks then you will have 120 legs.
So, the amount of legs will go up by 32 if you add 8 more desks.