I believe the answer would be A
Solution:
we have been asked to find
How much more time did Maria spend doing research ?
Maria spends doing research = 30%
and using email = 15% of a day (24 hours)
Time spent on research = 30% of 24 = 
Time spent on checking email = 15% of 24 = 
so, 
Hence , Maria spends 3.6 hours more on doing research than checking email.
If you increased 5 to 10, then I would have doubled the number 5 and this is a 100% increases.
If you increased 5 to 7.5, then this is 50% increase, because 50% of 5 is 2.5 and 5 + 2.5 = 7.5
If you increased 5 to 6, then this is a 20% increase,because 5 + 1 = 6 and 1 is 20% of 5
If you increased 5 to 7, then this is a 40% increase,because 5 increased by 2, 5 + 2 = 7, and 2/5 = 40%
If you increased 5 to x, then 5 was increased by x/5×100%
For example 5 to 9 is a4/5×100%=80% increase
So here 5 increases by 8, 5 + 3 = 8, thus the percentage increase is3/5×100%=0.006
