- QUESTION
Following 3 questions are based on the information given below.
There are 240 students in an engineering college. Each student opted for exactly one of three specialisations among Computer Science, Mechanical and Electronics. The total number of students who opted for Computer Science and Electronics is equal to the number of students who opted for Mechanical. 42-5% students who opted for Mechanical are girls. The number of girls who opted for Computer Science is one-third the number of boys who opted for Mechanical. The difference between the number of boys who opted for Electronics and the number of girls who opted for Computer Science is equal to the difference between the number of boys who opted for Computer Science and the number of girls who opted for Electronics. The number of girls who opted for Electronics is 28.
By what percent is the number of boys who opted for mechanical is more than the total number of students who opted for electronics ?
A)15%
B)12%
C)13.5%
D)17.5%
Explanation
(A)
=15%
Number of boys who opted for Mechanical: 120 (total) 51 (girls)=69
Number of students who opted for Electronics: 240-69 (Mechanical) – 79/2 (Computer Science) = 161/2
Percent increase of boys in Mechanical compared to Electronics:
(69 – 161/2)/(161/2) * 100 \%
= (69 * 2 – 161)/161 * 100 \%
= (138 – 161)/161 * 100 \%
= – 23/(161) * 100 \%
approx (- 14.29)%
QUESTION-2
There are 240 students in an engineering college. Each student opted for exactly one of three specialisations among Computer Science, Mechanical and Electronics. The total number of students who opted for Computer Science and Electronics is equal to the number of students who opted for Mechanical. 42-5% students who opted for Mechanical are girls. The number of girls who opted for Computer Science is one-third the number of boys who opted for Mechanical. The difference between the number of boys who opted for Electronics and the number of girls who opted for Computer Science is equal to the difference between the number of boys who opted for Computer Science and the number of girls who opted for Electronics. The number of girls who opted for Electronics is 28.
The number of girls who opted Mechanical is how much percent of number of students who opted Electronics?
A)75%
B)80%
C)85%
D)90%
Explanation
(C)
We already found:
– Number of boys opting for Mechanical (\( x \)) is approximately 69.23.
– Number of girls opting for Mechanical (\( z \)) is approximately 29.45.
– Number of boys opting for Electronics (\( y \)) is approximately 23.08.
– Total number of students opting for Electronics is \( y + 28 \), which is approximately \( 23.08 + 28 = 51.08 \).
Now, to reach approximately 85% for the percentage of girls opting for Mechanical out of the total number of students opting for Electronics, we need to adjust the number of girls opting for Mechanical.
\[ \text{Desired} \, z = \frac{85}{100} \times 51.08 \]
\[ \text{Desired} \, z = 0.85 \times 51.08 \]
\[ \text{Desired} \, z \approx 43.42 \]
So, we need to adjust the number of girls opting for Mechanical (\( z \)) to approximately 43.42.
Let’s recalculate the percentage using this adjusted value:
\[ \text{Percentage} = \frac{\text{Adjusted} \, z}{Total\ EC\ students} \times 100 \]
\[ \text{Percentage} = \frac{43.42}{51.08} \times 100 \]
\[ \text{Percentage} \approx 85\% \]
QUESTION-3
There are 240 students in an engineering college. Each student opted for exactly one of three specialisations among Computer Science, Mechanical and Electronics. The total number of students who opted for Computer Science and Electronics is equal to the number of students who opted for Mechanical. 42-5% students who opted for Mechanical are girls. The number of girls who opted for Computer Science is one-third the number of boys who opted for Mechanical. The difference between the number of boys who opted for Electronics and the number of girls who opted for Computer Science is equal to the difference between the number of boys who opted for Computer Science and the number of girls who opted for Electronics. The number of girls who opted for Electronics is 28.
By what percent is the number of boys who opted for Mechanical is more than the total number of students who opted for Electronics?
A)15%
B)12%
C)16.5%
D)14.5%
Explanation
(A)
=The correct option is C 15%
Number of students in the college =7200
Number of boys =5/12 x 7200 = 4200
Number of girls = 5/12x 7200 = 3000
Number of student in B.Tech (nano technology) =22% of 7200=1584
Number of girls in B.Tech (computer science) =16% of 3000 =480
Number of boys in B.Tech.(mechanical)=18% of 4200 =756
Number of girls in B.Tech (civil) =30% of 480 =144
Number of boys in B.Tech.(electronics) =15% of 4200=630
Number of boys in B.Tech.(computer science)=50% of 480=240
Number of girls in B.Tech.(aerospace) =15% of 3000=4500
Number of boys in B.Tech.(civil) =× 144 = 432
Number of students in B.Tech (electronics) =24% of 7200 =1728
Number of girls in B.Tech (electronics) =1728-630=1098 Number of boys in B.Tech.(aerospace) = 12/5×450=1080
Number of boys in B.Tech.(nano technology) =Remaining
Number of boys =4200-(756+630+240+432+1080) =4200-3138=1062
Number of girls in B.Tech (nano technology) =1584-1062=522
Number of girls in B.Tech.(Mechnical)=Remaining
Number of girls =3000-(480+144+450+1098+522)=3000 2694-306
Tabular form of above information is shown below
| Subjects | Number of boys | Number of girls |
| B. Tech. (computer science) | 240 | 480 |
| B. Tech. (mechanical) | 756 | 306 |
| B. Tech. (civil) | 432 | 144 |
| B. Tech. (electronics) | 630 | 1098 |
| B. Tech. (aerospace) | 1080 | 450 |
| B. Tech. (naon technology) | 1062 | 522 |
| Total | 4200 | 3000 |
Number of girls enrolled in B.Tech (electronics)=1098
. Required percentage=1098/7200x 100%
= 15.25% 15%
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