In an examination, a student scores 3 marks for every correct answer and looses 1 marks for every wrong answer. A student attempted all the 120 questions and scored 320 marks. Find the number of questions, he answered incorrectly.

The system of equations $4x + 14y = 18$ and $6x + 21y = 33$ has

Laxmi's father is 51 years old. He is three years older than three times Laxmi's age. The age of Laxmi is :

For what value of k, the system of equations $kx + 4y - k + 4 = 0$ and $16x + ky = k$ has an infinite number of solutions?

Which one of the following pair of linear equations is/are inconsistent?

A. x − y = 6, x − y = 13

B. 2x − 10y = 15, 7x − 35y =25

C. x − y = 15, 5x - 5y = 75

D. 7x − 9y − 3 = 0, 14x − 18y − 8 = 0

Choose the correct answer from the options given below:

The graphs of ax+by = c and dx+ey = f will be:

(A) parallel, if the system has no solution.

(B) coincident, if the system has finite numbers of solutions.

(C) intersecting, if the system has only one solution.

Which of the above statements is/ are correct?

Choose the correct answer from the options given below:

When thrice of x is added to 7, we get 13, then the value of x is :