How are proportions used in real life situations

Rob spent 25%, percent more time on his research project than he had planned. he spent an extra h hours on the project. which of the following expressions could represent the number of hours rob actually spent on the project? two answers

I’m really confused and need your assist me with this question i’ve never been taught

If set d is not the empty set but is a subset of set e, then which of the following is true? d ∩ e = d d ∩ e = e d ∩ e = ∅