The following table gives the life time of 400 neon lamps:
A bulb is selected at random. Find the probability that the lifetime of a selected bulb:
1. Less than 400 hrs
2. between 300 - 800 hours
3. At least 700 hours
Total number of bulbs = 400
1. Probability that the life of the selected bulb is less than 400 hrs
$=\frac{\text { No of bulbs having life less than } 400 \mathrm{hrs}}{\text { Total no of bulbs }}$
= 14/400
= 7/200
2. Probability that the life of the selected bulb is between 300 - 800 hrs
$=\frac{\text { No of bulbs having life less than } 400 \mathrm{hrs}}{\text { Total no of bulbs }}$
$=\frac{14+56+60+86+74}{200}$
= 290/400
= 29/40
3. Probability that the life of the selected bulb is at least 700 hrs
$=\frac{\text { No of bulbs having life at least } 700 \mathrm{hrs}}{\text { Total no of bulbs }}$
$=\frac{74+62+48}{400}$
= 184/400
= 23/50