Q. Of a total of 600 bolts, 20% are too large and 10% are too small. The remainder are considered to be suitable. If a bolt is selected at random, the probability that it will be suitable is
A) $\frac{1}{5}$
B) $\frac{7}{10}$
C) $\frac{1}{10}$
D) $\frac{3}{10}$
Explanation
(b)
Given total number of bolts=600
Numbers of large bolts=20% of 600
$= \frac{20}{100} \times 600 = 120$
Number of small bolts=10% of 600
$= \frac{10}{100} \times 600 = 60$
$\therefore$ Number of suitable bolts
$= 600 - 120 - 60 = 420$
$\therefore$ Probability of selecting suitable bolt
$= \frac{420}{600} = \frac{7}{10}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.