The first answer is 3/34 sec and the second answer is 15/34 sec.
Set up a proportion for these problems. For the first question,
340/1 = 30/x
Cross multiply:
340*x = 1*30
340x = 30
Divide both sides by 340:
340x/340=30/340
x = 30/340 = 3/34
For the second question,
340/1 = 150/x
Cross multiply:
340*x = 150*1
340x=150
Divide both sides by 340:
340x/340 = 150/340
x = 150/340 = 15/34
Alright, lets get started.
At the beginning of her training, she is able to run 2 miles without stopping means 2 will be in the addition when we will write the equation for her running miles.
Her goal is to increase her distance by three quarters of a mile each week.
Means in first week, she will add the distance =
miles
Suppose she runs x weeks, so shee will add distance = 
So, suppose she runs total number of miles = d, then

Where d is total numer of miles she runs
x is number of weeks : Answer
Hope it will help :)
When you have ratios and some unknowns you can create complex fractions from them.Bring them to the same denominator and solve for X.