Special Linear Equations

Rarely Tested

  • If the system of equations has n variables with n-1 equations, then the solution is indeterminate
  • If the system of equations has n variables with n-1 equations with some additional conditions like the variables are integers then the solution may be determinate
  • If the system of equations has n variables with n-1 equations then some combination of variables may be determinable.
  • For Example, if ax+by+cz=d and mx+ny+pz=q if a,b, and c are in Arithmetic progression and m,n and p are in AP then the sum x+y+z is determinable
  • In questions, sometimes we are given information that can be written as ax + by + cz =d, ex + fy + gz = h, and we will be asked to find the value of lx + my + nz.

    Here, the trick is to write lx + my + nz in terms of ax + by + cz and ex + fy + gz, for example: lx + my + nz = p( ax + by + cz) + q(ex + fy + gz) => lx + my + nz = p*d + q*h

Formula Video


Question 1

5 Cabbages, 12 Coconuts and 19 Brinjals cost Rs. 275. 23 Cabbages, 19 Coconutes and 15 Brinjals cost Rs.360. How much do 1 Coconut, 1 Brinjal and 1 Cabbage cost?

Question 2

The cost of 7 apples, 10 oranges and 13 pineapples is Rs. 25. The cost of 17 apples, 21 oranges and 25 pineapples is Rs.41. What is the cost of one apple, one orange and one pineapple?

Log in to view all questions

Go back to topics

Previous Year Stats

Special Linear Equations

1

question from CAT exam over the past 5 years

Join CAT 2026 course by 5-Time CAT 100%iler

Crack CAT 2026 & Other Exams with Cracku!