Topics

General Knowledge
General Science
General English
Aptitude
General Computer Science
General Intellingence and Reasoning
Current Affairs
Exams
Elementary Mathematics
English Literature

In an examination, a student scores 4 marks for every correct answer and losses 1 mark for every wrong answer. A student attempted all the 200 questions stud and scored 200 marks. Find the number of questions he answered correctly.

A) 82
B) 80
C) 68
D) 60

Correct Answer:


B) 80

Description for Correct answer:
Let the number of correct answers be x

and number of wrong answers be y

Then, 4x - y = 200 ...(i)

and x + y = 200 ...(ii)

On adding Eqs. (i) and (ii). we get

4x - y = 200

x + y = 200

5x = 400

Therefore, x = 80

Part of solved Linear Equations questions and answers : >> Aptitude >> Linear Equations

Comments

Similar Questions

1). The graphs of ax + by = c, dx + ey = f will be
I. parallel, if the system has no solution.
II. coincident, if the system has finite numbers of solutions.
III. intersecting, if the system has only one solution.
Which of the above statements are correct?

A). Only I and II

B). Only ll and Ill

C). Only I and III

D). I, II and Ill

2). If \( \Large 3^{x+y}=81 \) and \( \Large 81^{x-y}=3 \), then what is the value of x?

A). \( \Large \frac{17}{16} \)

B). \( \Large \frac{17}{8} \)

C). \( \Large \frac{17}{4} \)

D). \( \Large \frac{15}{4} \)

3). Ten chairs and six tables together cost Rs.6200, three chairs and two tables together cost Rs.1900. The cost of 4 chairs and 5 tables is

A). Rs.3000

B). Rs.3300

C). Rs.3500

D). Rs.3800

4). The system of equations 3x + y - 4 = 0 and 6x + 2y - 8 = 0 has

A). a unique solution x = 1, y=1

B). a unique solution x = 0, y = 4

C). no solution

D). infinite solutions

5). If x+ y - 7 = 0 and 3x + y -13 = 0, then what is \( \Large 4x^{2} + y^{2} + 4xy\) equal to?

A). 75

B). 85

C). 91

D). 100

6). The solution of the equations \( \Large \frac{p}{x}+\frac{q}{y} \ and \ \frac{q}{x}+\frac{p}{y} \) n is

A). \( \Large x=\frac{q^{2}-p^{2}}{mp-nq}, y=\frac{p^{2}-q^{2}}{np-mq} \)

B). \( \Large x=\frac{p^{2}-q^{2}}{mp-nq}, y=\frac{q^{2}-p^{2}}{np-mq} \)

C). \( \Large x=\frac{p^{2}-q^{2}}{mp-nq}, y=\frac{p^{2}-q^{2}}{np-mq} \)

D). \( \Large x=\frac{q^{2}-p^{2}}{mp-nq}, y=\frac{q^{2}-p^{2}}{np-mq} \)

7). If \( \Large \frac{3}{x+y}+\frac{2}{x-y}=2 \) and \( \Large \frac{9}{x+y}-\frac{4}{x-y}=1 \), then what is the value of \( \Large \frac{x}{y} \)?

A). \( \Large \frac{3}{2} \)

B). 5

C). \( \Large \frac{2}{3} \)

D). \( \Large \frac{1}{5} \)

8). If \( \Large \frac{a}{b}-\frac{b}{a}=\frac{x}{y} \) and \( \Large \frac{a}{b}+\frac{b}{a}= x - y \) , then what is the value of x?

A). \( \Large \frac{a+b}{a} \)

B). \( \Large \frac{a+b}{b} \)

C). \( \Large \frac{a-b}{a} \)

D). None of these

9). If \( \Large \frac{x}{2}+\frac{y}{3}=4 \) and \( \Large \frac{2}{x}+\frac{3}{y}=1 \) then what is x + y equal to?

A). 11

B). 10

C). 9

D). 8

10). A mason can build a tank in 12 h. After working for 6 h, he took the help of a boy and finished the work in another 5 h. The time that the boy will take alone to complete the work is

A). 30 h

B). 45 h

C). 60 h

D). 64 h