6 Ranjit goes to mathematics lectures and physics lectures. The length, in minutes, of a mathematics lecture is modelled by the variable \(X\) with distribution \(\mathrm { N } \left( 36,3.5 ^ { 2 } \right)\). The length, in minutes, of a physics lecture is modelled by the independent variable \(Y\) with distribution \(\mathrm { N } \left( 55,5.2 ^ { 2 } \right)\).
- Find the probability that the total length of two mathematics lectures and one physics lecture is less than 140 minutes.
- Ranjit calculates how long he will need to spend revising the content of each lecture as follows. Each minute of a mathematics lecture requires 1 minute of revision and each minute of a physics lecture requires \(1 \frac { 1 } { 2 }\) minutes of revision. Find the probability that the total revision time required for one mathematics lecture and one physics lecture is more than 100 minutes.