$A$ teacher wanted to analyze the performance of two sections of students in a mathematics test of $100$ marks. Looking at their performances,she found that a few students got under $20$ marks and a few got $70$ marks or above. So she decided to group them into intervals of varying sizes as follows: $0-20, 20-30, ..., 60-70, 70-100$. Then she formed the following table:
Marks Number of students $0-20$ $7$ $20-30$ $10$ $30-40$ $10$ $40-50$ $20$ $50-60$ $20$ $60-70$ $15$ $70$ and above $8$ Total $90$
$(i)$ Find the probability that a student obtained less than $20\%$ in the mathematics test.
$(ii)$ Find the probability that a student obtained marks $60$ or above.
| Marks | Number of students |
| $0-20$ | $7$ |
| $20-30$ | $10$ |
| $30-40$ | $10$ |
| $40-50$ | $20$ |
| $50-60$ | $20$ |
| $60-70$ | $15$ |
| $70$ and above | $8$ |
| Total | $90$ |
$(i)$ Find the probability that a student obtained less than $20\%$ in the mathematics test.
$(ii)$ Find the probability that a student obtained marks $60$ or above.
- A$\frac{7}{39}, 53/90$
- B$\frac{27}{90}, 69/90$
- C$\frac{7}{19}, 23/90$
- D$\frac{7}{90}, 23/90$
Explore More
Similar Questions
On one page of a telephone directory,there were $200$ telephone numbers. The frequency distribution of their unit place digit (for example,in the number $25828573$,the unit place digit is $3$) is given in the table below:
Digit $0, 1, 2, 3, 4, 5, 6, 7, 8, 9$ Frequency $22, 26, 22, 22, 20, 10, 14, 28, 16, 20$
Without looking at the page,a number is chosen at random. What is the probability that the digit in its unit place is $6$?
| Digit | $0, 1, 2, 3, 4, 5, 6, 7, 8, 9$ |
| Frequency | $22, 26, 22, 22, 20, 10, 14, 28, 16, 20$ |
Without looking at the page,a number is chosen at random. What is the probability that the digit in its unit place is $6$?
Medium
View SolutionNote the frequency of two-wheelers, three-wheelers, and four-wheelers passing by your school gate during a specific time interval. Calculate the probability that any one vehicle chosen from the total vehicles observed is a two-wheeler.
Medium
View SolutionThe following frequency distribution table shows the blood groups of $30$ students of a class. Use this table to determine the probability that a student of this class,selected at random,has blood group $AB$.
Blood group Number of students $A$ $9$ $B$ $6$ $AB$ $3$ $O$ $12$ Total $30$
| Blood group | Number of students |
| $A$ | $9$ |
| $B$ | $6$ |
| $AB$ | $3$ |
| $O$ | $12$ |
| Total | $30$ |
Easy
View SolutionAn organisation selected $2400$ families at random and surveyed them to determine a relationship between income level and the number of vehicles in a family. The information gathered is listed in the table below:
Monthly income (in Rs.) / Vehicles per family $0$ $1$ $2$ Above $2$ Less than $7000$ $10$ $160$ $25$ $0$ $7000 - 10000$ $0$ $305$ $27$ $2$ $10000 - 13000$ $1$ $535$ $29$ $1$ $13000 - 16000$ $2$ $469$ $59$ $25$ $16000$ or more $1$ $579$ $82$ $88$
Suppose a family is chosen. Find the probability that the family chosen is:
$(i)$ Earning Rs. $10000 - 13000$ per month and owning exactly $2$ vehicles.
$(ii)$ Earning Rs. $16000$ or more per month and owning exactly $1$ vehicle.
$(iii)$ Earning less than Rs. $7000$ per month and does not own any vehicle.
$(iv)$ Earning Rs. $13000 - 16000$ per month and owning more than $2$ vehicles.
$(v)$ Owning not more than $1$ vehicle.
| Monthly income (in Rs.) / Vehicles per family | $0$ | $1$ | $2$ | Above $2$ |
| Less than $7000$ | $10$ | $160$ | $25$ | $0$ |
| $7000 - 10000$ | $0$ | $305$ | $27$ | $2$ |
| $10000 - 13000$ | $1$ | $535$ | $29$ | $1$ |
| $13000 - 16000$ | $2$ | $469$ | $59$ | $25$ |
| $16000$ or more | $1$ | $579$ | $82$ | $88$ |
Suppose a family is chosen. Find the probability that the family chosen is:
$(i)$ Earning Rs. $10000 - 13000$ per month and owning exactly $2$ vehicles.
$(ii)$ Earning Rs. $16000$ or more per month and owning exactly $1$ vehicle.
$(iii)$ Earning less than Rs. $7000$ per month and does not own any vehicle.
$(iv)$ Earning Rs. $13000 - 16000$ per month and owning more than $2$ vehicles.
$(v)$ Owning not more than $1$ vehicle.
Medium
View SolutionAn insurance company selected $2000$ drivers at random in a particular city to find a relationship between age and accidents. The data obtained are given in the following table:
Age of drivers (in years) $0$ accidents $1$ accident $2$ accidents $3$ accidents Over $3$ accidents $18-29$ $440$ $160$ $110$ $61$ $35$ $30-50$ $505$ $125$ $60$ $22$ $18$ Above $50$ $360$ $45$ $35$ $15$ $9$
Find the probabilities of the following events for a driver chosen at random from the city:
$(i)$ Being $18-29$ years of age and having exactly $3$ accidents in one year.
$(ii)$ Being $30-50$ years of age and having one or more accidents in a year.
$(iii)$ Having no accidents in one year.
| Age of drivers (in years) | $0$ accidents | $1$ accident | $2$ accidents | $3$ accidents | Over $3$ accidents |
| $18-29$ | $440$ | $160$ | $110$ | $61$ | $35$ |
| $30-50$ | $505$ | $125$ | $60$ | $22$ | $18$ |
| Above $50$ | $360$ | $45$ | $35$ | $15$ | $9$ |
Find the probabilities of the following events for a driver chosen at random from the city:
$(i)$ Being $18-29$ years of age and having exactly $3$ accidents in one year.
$(ii)$ Being $30-50$ years of age and having one or more accidents in a year.
$(iii)$ Having no accidents in one year.
Medium
View SolutionVedclass Products
For Students
Vedclass Test Series
Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.
Start Free TrialFor Teachers
Exam Paper Generator
Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.
Try FreeFor Institutes
Online Exam Module
Live online exams with unlimited students, 360° analytics & white-label branding.
See Demo