160 is 100% of 160, 480 is 4 times that. So 400%
First you need to divide 7 and 15, and the answer you get is 8, so 8+7=15. 8 will be your answer.
2/3 hour =2/3×60 min=40 min
2/3 hour=2/3×3600 seconds=2400seconds
Check picture below, radius = r = 15, thus