In Saybold method: if you performed three tests for viscosity measurement their results were as following: (80% lubricating oil, 20% benzene XXXXXXXXXXseconds (60% lubricating oil, 40% benzene...

In Saybold method: if you performed three tests for viscosity measurement their results were as following: (80% lubricating oil, 20% benzene)-------50 seconds (60% lubricating oil, 40% benzene)-------20 seconds (40% lubricating oil, 60% benzene)-------13 seconds Then find the following: A-- The viscosity value when benzene concentration equal to (50 and 70)% ? B--The benzene concentration when viscosity equal to ( 35 and 55) seconds?