Question

One is asked to say two digit number what is t
he probabilty of that number being a multiple of 5

Answer 1

$Probability=\frac{Sum-of-favourable-outcomes}{No.-of-outcomes}$

∴ Total no. of two digit no.s = 100 - 10

                                              =  90

And,      

Two-digit no.s which are multiples of 5 = 10, 15, 20, 25, 30, 35, 40, 45, 50, 55,                    

                                                                    60, 65, 75, 80, 85, 90, 95.

∴ probability ( no. multiple of 5) =

$=\frac{10+15+20+25+30+35+40+45+50+55+60+65+70+75+80+85+90+95}{90}\\\\=\frac{945}{90}\\\\=10.5$

Hence, the probability of being a number a multiple of 5 is 10.5.        Ans.