Can you help me with two this question? just multiple choice but need a reason why we choose those answer.

Imagine an old single-programming system equipped with a CPU, a disk, a printer, and a reader. At the end of a program execution, the system reports the accumulated percentage usage of the four components. The exact pattern of the program's activities is not known: the report includes one number per device. According to the report, a certain program spends 70% of its time using the CPU, with the remaining 30% equally partitioned among the remaining three hardware components. This is all we know about the program. By how much will the execution time of the program decrease when the disk is replaced with a new version being twice as fast as the previous one? a. by 1% b. by 5% c. by 10% d. by 20% e. by 40% f. by 50% g. it can be any number between 0% and 30% Question 7: Some smart student from one of our competitor schools was hired to implement a page replacement strategy for a new operating system. Trying to be creative, the student implemented a strategy named LIFO which basically operates as FIFO, except that instead of the oldest page, it victimizes the newest page, i.e., one that was most recently fetched into memory. Faced with dismissal, the student argues that there are programs for which the strategy generates fewer page faults than LRU. Which one of the following page reference strings is going to generate fewer page faults under LIFO than under LRU when operating with 3 frames of memory? a. 123434343434 b. 123414242323 c. 123412123234 d. 123412341234