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