Paper 6 May/June 2003 MATHEMATICH (9709/6) A Levels
لطفا برای اطمینان از عملکرد و تجربه بهتر از مرورگرهای مدرن و به روز مانند کروم یا فایرفاکس استفاده کنید.

Ranjit goes to mathematics lectures and physics lectures. The length, in minutes, of a mathematics lecture is modelled by the variable $X$ with distribution $N\left( {36,{\text{ }}{{3.5}^2}} \right)$. The length, in minutes, of a physics lecture is modelled by the independent variable $Y$ with distribution $N\left( {55,{\text{ }}{{5.2}^2}} \right)$.
a) Find the probability that the total length of two mathematics lectures and one physics lecture is less than 140 minutes.
…